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 #include "opt_hwpmc_hooks.h" 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/disk.h> 51 #include <sys/fail.h> 52 #include <sys/fcntl.h> 53 #include <sys/file.h> 54 #include <sys/kdb.h> 55 #include <sys/ktr.h> 56 #include <sys/stat.h> 57 #include <sys/priv.h> 58 #include <sys/proc.h> 59 #include <sys/limits.h> 60 #include <sys/lock.h> 61 #include <sys/mman.h> 62 #include <sys/mount.h> 63 #include <sys/mutex.h> 64 #include <sys/namei.h> 65 #include <sys/vnode.h> 66 #include <sys/dirent.h> 67 #include <sys/bio.h> 68 #include <sys/buf.h> 69 #include <sys/filio.h> 70 #include <sys/resourcevar.h> 71 #include <sys/rwlock.h> 72 #include <sys/prng.h> 73 #include <sys/sx.h> 74 #include <sys/sleepqueue.h> 75 #include <sys/sysctl.h> 76 #include <sys/ttycom.h> 77 #include <sys/conf.h> 78 #include <sys/syslog.h> 79 #include <sys/unistd.h> 80 #include <sys/user.h> 81 #include <sys/ktrace.h> 82 83 #include <security/audit/audit.h> 84 #include <security/mac/mac_framework.h> 85 86 #include <vm/vm.h> 87 #include <vm/vm_extern.h> 88 #include <vm/pmap.h> 89 #include <vm/vm_map.h> 90 #include <vm/vm_object.h> 91 #include <vm/vm_page.h> 92 #include <vm/vm_pager.h> 93 94 #ifdef HWPMC_HOOKS 95 #include <sys/pmckern.h> 96 #endif 97 98 static fo_rdwr_t vn_read; 99 static fo_rdwr_t vn_write; 100 static fo_rdwr_t vn_io_fault; 101 static fo_truncate_t vn_truncate; 102 static fo_ioctl_t vn_ioctl; 103 static fo_poll_t vn_poll; 104 static fo_kqfilter_t vn_kqfilter; 105 static fo_close_t vn_closefile; 106 static fo_mmap_t vn_mmap; 107 static fo_fallocate_t vn_fallocate; 108 static fo_fspacectl_t vn_fspacectl; 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_fspacectl = vn_fspacectl, 127 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 128 }; 129 130 const u_int io_hold_cnt = 16; 131 static int vn_io_fault_enable = 1; 132 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RWTUN, 133 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 134 static int vn_io_fault_prefault = 0; 135 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RWTUN, 136 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 137 static int vn_io_pgcache_read_enable = 1; 138 SYSCTL_INT(_debug, OID_AUTO, vn_io_pgcache_read_enable, CTLFLAG_RWTUN, 139 &vn_io_pgcache_read_enable, 0, 140 "Enable copying from page cache for reads, avoiding fs"); 141 static u_long vn_io_faults_cnt; 142 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 143 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 144 145 static int vfs_allow_read_dir = 0; 146 SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW, 147 &vfs_allow_read_dir, 0, 148 "Enable read(2) of directory by root for filesystems that support it"); 149 150 /* 151 * Returns true if vn_io_fault mode of handling the i/o request should 152 * be used. 153 */ 154 static bool 155 do_vn_io_fault(struct vnode *vp, struct uio *uio) 156 { 157 struct mount *mp; 158 159 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 160 (mp = vp->v_mount) != NULL && 161 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 162 } 163 164 /* 165 * Structure used to pass arguments to vn_io_fault1(), to do either 166 * file- or vnode-based I/O calls. 167 */ 168 struct vn_io_fault_args { 169 enum { 170 VN_IO_FAULT_FOP, 171 VN_IO_FAULT_VOP 172 } kind; 173 struct ucred *cred; 174 int flags; 175 union { 176 struct fop_args_tag { 177 struct file *fp; 178 fo_rdwr_t *doio; 179 } fop_args; 180 struct vop_args_tag { 181 struct vnode *vp; 182 } vop_args; 183 } args; 184 }; 185 186 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 187 struct vn_io_fault_args *args, struct thread *td); 188 189 int 190 vn_open(struct nameidata *ndp, int *flagp, int cmode, struct file *fp) 191 { 192 struct thread *td = curthread; 193 194 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 195 } 196 197 static uint64_t 198 open2nameif(int fmode, u_int vn_open_flags) 199 { 200 uint64_t res; 201 202 res = ISOPEN | LOCKLEAF; 203 if ((fmode & O_RESOLVE_BENEATH) != 0) 204 res |= RBENEATH; 205 if ((fmode & O_EMPTY_PATH) != 0) 206 res |= EMPTYPATH; 207 if ((fmode & FREAD) != 0) 208 res |= OPENREAD; 209 if ((fmode & FWRITE) != 0) 210 res |= OPENWRITE; 211 if ((vn_open_flags & VN_OPEN_NOAUDIT) == 0) 212 res |= AUDITVNODE1; 213 if ((vn_open_flags & VN_OPEN_NOCAPCHECK) != 0) 214 res |= NOCAPCHECK; 215 if ((vn_open_flags & VN_OPEN_WANTIOCTLCAPS) != 0) 216 res |= WANTIOCTLCAPS; 217 return (res); 218 } 219 220 /* 221 * Common code for vnode open operations via a name lookup. 222 * Lookup the vnode and invoke VOP_CREATE if needed. 223 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 224 * 225 * Note that this does NOT free nameidata for the successful case, 226 * due to the NDINIT being done elsewhere. 227 */ 228 int 229 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 230 struct ucred *cred, struct file *fp) 231 { 232 struct vnode *vp; 233 struct mount *mp; 234 struct vattr vat; 235 struct vattr *vap = &vat; 236 int fmode, error; 237 bool first_open; 238 239 restart: 240 first_open = false; 241 fmode = *flagp; 242 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 243 O_EXCL | O_DIRECTORY) || 244 (fmode & (O_CREAT | O_EMPTY_PATH)) == (O_CREAT | O_EMPTY_PATH)) 245 return (EINVAL); 246 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 247 ndp->ni_cnd.cn_nameiop = CREATE; 248 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 249 /* 250 * Set NOCACHE to avoid flushing the cache when 251 * rolling in many files at once. 252 * 253 * Set NC_KEEPPOSENTRY to keep positive entries if they already 254 * exist despite NOCACHE. 255 */ 256 ndp->ni_cnd.cn_flags |= LOCKPARENT | NOCACHE | NC_KEEPPOSENTRY; 257 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 258 ndp->ni_cnd.cn_flags |= FOLLOW; 259 if ((vn_open_flags & VN_OPEN_INVFS) == 0) 260 bwillwrite(); 261 if ((error = namei(ndp)) != 0) 262 return (error); 263 if (ndp->ni_vp == NULL) { 264 VATTR_NULL(vap); 265 vap->va_type = VREG; 266 vap->va_mode = cmode; 267 if (fmode & O_EXCL) 268 vap->va_vaflags |= VA_EXCLUSIVE; 269 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 270 NDFREE_PNBUF(ndp); 271 vput(ndp->ni_dvp); 272 if ((error = vn_start_write(NULL, &mp, 273 V_XSLEEP | V_PCATCH)) != 0) 274 return (error); 275 NDREINIT(ndp); 276 goto restart; 277 } 278 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 279 ndp->ni_cnd.cn_flags |= MAKEENTRY; 280 #ifdef MAC 281 error = mac_vnode_check_create(cred, ndp->ni_dvp, 282 &ndp->ni_cnd, vap); 283 if (error == 0) 284 #endif 285 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 286 &ndp->ni_cnd, vap); 287 vp = ndp->ni_vp; 288 if (error == 0 && (fmode & O_EXCL) != 0 && 289 (fmode & (O_EXLOCK | O_SHLOCK)) != 0) { 290 VI_LOCK(vp); 291 vp->v_iflag |= VI_FOPENING; 292 VI_UNLOCK(vp); 293 first_open = true; 294 } 295 VOP_VPUT_PAIR(ndp->ni_dvp, error == 0 ? &vp : NULL, 296 false); 297 vn_finished_write(mp); 298 if (error) { 299 NDFREE_PNBUF(ndp); 300 if (error == ERELOOKUP) { 301 NDREINIT(ndp); 302 goto restart; 303 } 304 return (error); 305 } 306 fmode &= ~O_TRUNC; 307 } else { 308 if (ndp->ni_dvp == ndp->ni_vp) 309 vrele(ndp->ni_dvp); 310 else 311 vput(ndp->ni_dvp); 312 ndp->ni_dvp = NULL; 313 vp = ndp->ni_vp; 314 if (fmode & O_EXCL) { 315 error = EEXIST; 316 goto bad; 317 } 318 if (vp->v_type == VDIR) { 319 error = EISDIR; 320 goto bad; 321 } 322 fmode &= ~O_CREAT; 323 } 324 } else { 325 ndp->ni_cnd.cn_nameiop = LOOKUP; 326 ndp->ni_cnd.cn_flags = open2nameif(fmode, vn_open_flags); 327 ndp->ni_cnd.cn_flags |= (fmode & O_NOFOLLOW) != 0 ? NOFOLLOW : 328 FOLLOW; 329 if ((fmode & FWRITE) == 0) 330 ndp->ni_cnd.cn_flags |= LOCKSHARED; 331 if ((error = namei(ndp)) != 0) 332 return (error); 333 vp = ndp->ni_vp; 334 } 335 error = vn_open_vnode(vp, fmode, cred, curthread, fp); 336 if (first_open) { 337 VI_LOCK(vp); 338 vp->v_iflag &= ~VI_FOPENING; 339 wakeup(vp); 340 VI_UNLOCK(vp); 341 } 342 if (error) 343 goto bad; 344 *flagp = fmode; 345 return (0); 346 bad: 347 NDFREE_PNBUF(ndp); 348 vput(vp); 349 *flagp = fmode; 350 ndp->ni_vp = NULL; 351 return (error); 352 } 353 354 static int 355 vn_open_vnode_advlock(struct vnode *vp, int fmode, struct file *fp) 356 { 357 struct flock lf; 358 int error, lock_flags, type; 359 360 ASSERT_VOP_LOCKED(vp, "vn_open_vnode_advlock"); 361 if ((fmode & (O_EXLOCK | O_SHLOCK)) == 0) 362 return (0); 363 KASSERT(fp != NULL, ("open with flock requires fp")); 364 if (fp->f_type != DTYPE_NONE && fp->f_type != DTYPE_VNODE) 365 return (EOPNOTSUPP); 366 367 lock_flags = VOP_ISLOCKED(vp); 368 VOP_UNLOCK(vp); 369 370 lf.l_whence = SEEK_SET; 371 lf.l_start = 0; 372 lf.l_len = 0; 373 lf.l_type = (fmode & O_EXLOCK) != 0 ? F_WRLCK : F_RDLCK; 374 type = F_FLOCK; 375 if ((fmode & FNONBLOCK) == 0) 376 type |= F_WAIT; 377 if ((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) 378 type |= F_FIRSTOPEN; 379 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 380 if (error == 0) 381 fp->f_flag |= FHASLOCK; 382 383 vn_lock(vp, lock_flags | LK_RETRY); 384 return (error); 385 } 386 387 /* 388 * Common code for vnode open operations once a vnode is located. 389 * Check permissions, and call the VOP_OPEN routine. 390 */ 391 int 392 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 393 struct thread *td, struct file *fp) 394 { 395 accmode_t accmode; 396 int error; 397 398 if (vp->v_type == VLNK) { 399 if ((fmode & O_PATH) == 0 || (fmode & FEXEC) != 0) 400 return (EMLINK); 401 } 402 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 403 return (ENOTDIR); 404 405 accmode = 0; 406 if ((fmode & O_PATH) == 0) { 407 if (vp->v_type == VSOCK) 408 return (EOPNOTSUPP); 409 if ((fmode & (FWRITE | O_TRUNC)) != 0) { 410 if (vp->v_type == VDIR) 411 return (EISDIR); 412 accmode |= VWRITE; 413 } 414 if ((fmode & FREAD) != 0) 415 accmode |= VREAD; 416 if ((fmode & O_APPEND) && (fmode & FWRITE)) 417 accmode |= VAPPEND; 418 #ifdef MAC 419 if ((fmode & O_CREAT) != 0) 420 accmode |= VCREAT; 421 #endif 422 } 423 if ((fmode & FEXEC) != 0) 424 accmode |= VEXEC; 425 #ifdef MAC 426 if ((fmode & O_VERIFY) != 0) 427 accmode |= VVERIFY; 428 error = mac_vnode_check_open(cred, vp, accmode); 429 if (error != 0) 430 return (error); 431 432 accmode &= ~(VCREAT | VVERIFY); 433 #endif 434 if ((fmode & O_CREAT) == 0 && accmode != 0) { 435 error = VOP_ACCESS(vp, accmode, cred, td); 436 if (error != 0) 437 return (error); 438 } 439 if ((fmode & O_PATH) != 0) { 440 if (vp->v_type != VFIFO && vp->v_type != VSOCK && 441 VOP_ACCESS(vp, VREAD, cred, td) == 0) 442 fp->f_flag |= FKQALLOWED; 443 return (0); 444 } 445 446 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 447 vn_lock(vp, LK_UPGRADE | LK_RETRY); 448 error = VOP_OPEN(vp, fmode, cred, td, fp); 449 if (error != 0) 450 return (error); 451 452 error = vn_open_vnode_advlock(vp, fmode, fp); 453 if (error == 0 && (fmode & FWRITE) != 0) { 454 error = VOP_ADD_WRITECOUNT(vp, 1); 455 if (error == 0) { 456 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 457 __func__, vp, vp->v_writecount); 458 } 459 } 460 461 /* 462 * Error from advlock or VOP_ADD_WRITECOUNT() still requires 463 * calling VOP_CLOSE() to pair with earlier VOP_OPEN(). 464 */ 465 if (error != 0) { 466 if (fp != NULL) { 467 /* 468 * Arrange the call by having fdrop() to use 469 * vn_closefile(). This is to satisfy 470 * filesystems like devfs or tmpfs, which 471 * override fo_close(). 472 */ 473 fp->f_flag |= FOPENFAILED; 474 fp->f_vnode = vp; 475 if (fp->f_ops == &badfileops) { 476 fp->f_type = DTYPE_VNODE; 477 fp->f_ops = &vnops; 478 } 479 vref(vp); 480 } else { 481 /* 482 * If there is no fp, due to kernel-mode open, 483 * we can call VOP_CLOSE() now. 484 */ 485 if ((vp->v_type == VFIFO || 486 !MNT_EXTENDED_SHARED(vp->v_mount)) && 487 VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 488 vn_lock(vp, LK_UPGRADE | LK_RETRY); 489 (void)VOP_CLOSE(vp, fmode & (FREAD | FWRITE | FEXEC), 490 cred, td); 491 } 492 } 493 494 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 495 return (error); 496 497 } 498 499 /* 500 * Check for write permissions on the specified vnode. 501 * Prototype text segments cannot be written. 502 * It is racy. 503 */ 504 int 505 vn_writechk(struct vnode *vp) 506 { 507 508 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 509 /* 510 * If there's shared text associated with 511 * the vnode, try to free it up once. If 512 * we fail, we can't allow writing. 513 */ 514 if (VOP_IS_TEXT(vp)) 515 return (ETXTBSY); 516 517 return (0); 518 } 519 520 /* 521 * Vnode close call 522 */ 523 static int 524 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred, 525 struct thread *td, bool keep_ref) 526 { 527 struct mount *mp; 528 int error, lock_flags; 529 530 lock_flags = vp->v_type != VFIFO && MNT_EXTENDED_SHARED(vp->v_mount) ? 531 LK_SHARED : LK_EXCLUSIVE; 532 533 vn_start_write(vp, &mp, V_WAIT); 534 vn_lock(vp, lock_flags | LK_RETRY); 535 AUDIT_ARG_VNODE1(vp); 536 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) { 537 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 538 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 539 __func__, vp, vp->v_writecount); 540 } 541 error = VOP_CLOSE(vp, flags, file_cred, td); 542 if (keep_ref) 543 VOP_UNLOCK(vp); 544 else 545 vput(vp); 546 vn_finished_write(mp); 547 return (error); 548 } 549 550 int 551 vn_close(struct vnode *vp, int flags, struct ucred *file_cred, 552 struct thread *td) 553 { 554 555 return (vn_close1(vp, flags, file_cred, td, false)); 556 } 557 558 /* 559 * Heuristic to detect sequential operation. 560 */ 561 static int 562 sequential_heuristic(struct uio *uio, struct file *fp) 563 { 564 enum uio_rw rw; 565 566 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 567 568 rw = uio->uio_rw; 569 if (fp->f_flag & FRDAHEAD) 570 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 571 572 /* 573 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 574 * that the first I/O is normally considered to be slightly 575 * sequential. Seeking to offset 0 doesn't change sequentiality 576 * unless previous seeks have reduced f_seqcount to 0, in which 577 * case offset 0 is not special. 578 */ 579 if ((uio->uio_offset == 0 && fp->f_seqcount[rw] > 0) || 580 uio->uio_offset == fp->f_nextoff[rw]) { 581 /* 582 * f_seqcount is in units of fixed-size blocks so that it 583 * depends mainly on the amount of sequential I/O and not 584 * much on the number of sequential I/O's. The fixed size 585 * of 16384 is hard-coded here since it is (not quite) just 586 * a magic size that works well here. This size is more 587 * closely related to the best I/O size for real disks than 588 * to any block size used by software. 589 */ 590 if (uio->uio_resid >= IO_SEQMAX * 16384) 591 fp->f_seqcount[rw] = IO_SEQMAX; 592 else { 593 fp->f_seqcount[rw] += howmany(uio->uio_resid, 16384); 594 if (fp->f_seqcount[rw] > IO_SEQMAX) 595 fp->f_seqcount[rw] = IO_SEQMAX; 596 } 597 return (fp->f_seqcount[rw] << IO_SEQSHIFT); 598 } 599 600 /* Not sequential. Quickly draw-down sequentiality. */ 601 if (fp->f_seqcount[rw] > 1) 602 fp->f_seqcount[rw] = 1; 603 else 604 fp->f_seqcount[rw] = 0; 605 return (0); 606 } 607 608 /* 609 * Package up an I/O request on a vnode into a uio and do it. 610 */ 611 int 612 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 613 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 614 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 615 { 616 struct uio auio; 617 struct iovec aiov; 618 struct mount *mp; 619 struct ucred *cred; 620 void *rl_cookie; 621 struct vn_io_fault_args args; 622 int error, lock_flags; 623 624 if (offset < 0 && vp->v_type != VCHR) 625 return (EINVAL); 626 auio.uio_iov = &aiov; 627 auio.uio_iovcnt = 1; 628 aiov.iov_base = base; 629 aiov.iov_len = len; 630 auio.uio_resid = len; 631 auio.uio_offset = offset; 632 auio.uio_segflg = segflg; 633 auio.uio_rw = rw; 634 auio.uio_td = td; 635 error = 0; 636 637 if ((ioflg & IO_NODELOCKED) == 0) { 638 if ((ioflg & IO_RANGELOCKED) == 0) { 639 if (rw == UIO_READ) { 640 rl_cookie = vn_rangelock_rlock(vp, offset, 641 offset + len); 642 } else if ((ioflg & IO_APPEND) != 0) { 643 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 644 } else { 645 rl_cookie = vn_rangelock_wlock(vp, offset, 646 offset + len); 647 } 648 } else 649 rl_cookie = NULL; 650 mp = NULL; 651 if (rw == UIO_WRITE) { 652 if (vp->v_type != VCHR && 653 (error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH)) 654 != 0) 655 goto out; 656 lock_flags = vn_lktype_write(mp, vp); 657 } else 658 lock_flags = LK_SHARED; 659 vn_lock(vp, lock_flags | LK_RETRY); 660 } else 661 rl_cookie = NULL; 662 663 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 664 #ifdef MAC 665 if ((ioflg & IO_NOMACCHECK) == 0) { 666 if (rw == UIO_READ) 667 error = mac_vnode_check_read(active_cred, file_cred, 668 vp); 669 else 670 error = mac_vnode_check_write(active_cred, file_cred, 671 vp); 672 } 673 #endif 674 if (error == 0) { 675 if (file_cred != NULL) 676 cred = file_cred; 677 else 678 cred = active_cred; 679 if (do_vn_io_fault(vp, &auio)) { 680 args.kind = VN_IO_FAULT_VOP; 681 args.cred = cred; 682 args.flags = ioflg; 683 args.args.vop_args.vp = vp; 684 error = vn_io_fault1(vp, &auio, &args, td); 685 } else if (rw == UIO_READ) { 686 error = VOP_READ(vp, &auio, ioflg, cred); 687 } else /* if (rw == UIO_WRITE) */ { 688 error = VOP_WRITE(vp, &auio, ioflg, cred); 689 } 690 } 691 if (aresid) 692 *aresid = auio.uio_resid; 693 else 694 if (auio.uio_resid && error == 0) 695 error = EIO; 696 if ((ioflg & IO_NODELOCKED) == 0) { 697 VOP_UNLOCK(vp); 698 if (mp != NULL) 699 vn_finished_write(mp); 700 } 701 out: 702 if (rl_cookie != NULL) 703 vn_rangelock_unlock(vp, rl_cookie); 704 return (error); 705 } 706 707 /* 708 * Package up an I/O request on a vnode into a uio and do it. The I/O 709 * request is split up into smaller chunks and we try to avoid saturating 710 * the buffer cache while potentially holding a vnode locked, so we 711 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 712 * to give other processes a chance to lock the vnode (either other processes 713 * core'ing the same binary, or unrelated processes scanning the directory). 714 */ 715 int 716 vn_rdwr_inchunks(enum uio_rw rw, struct vnode *vp, void *base, size_t len, 717 off_t offset, enum uio_seg segflg, int ioflg, struct ucred *active_cred, 718 struct ucred *file_cred, size_t *aresid, struct thread *td) 719 { 720 int error = 0; 721 ssize_t iaresid; 722 723 do { 724 int chunk; 725 726 /* 727 * Force `offset' to a multiple of MAXBSIZE except possibly 728 * for the first chunk, so that filesystems only need to 729 * write full blocks except possibly for the first and last 730 * chunks. 731 */ 732 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 733 734 if (chunk > len) 735 chunk = len; 736 if (rw != UIO_READ && vp->v_type == VREG) 737 bwillwrite(); 738 iaresid = 0; 739 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 740 ioflg, active_cred, file_cred, &iaresid, td); 741 len -= chunk; /* aresid calc already includes length */ 742 if (error) 743 break; 744 offset += chunk; 745 base = (char *)base + chunk; 746 kern_yield(PRI_USER); 747 } while (len); 748 if (aresid) 749 *aresid = len + iaresid; 750 return (error); 751 } 752 753 #if OFF_MAX <= LONG_MAX 754 off_t 755 foffset_lock(struct file *fp, int flags) 756 { 757 volatile short *flagsp; 758 off_t res; 759 short state; 760 761 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 762 763 if ((flags & FOF_NOLOCK) != 0) 764 return (atomic_load_long(&fp->f_offset)); 765 766 /* 767 * According to McKusick the vn lock was protecting f_offset here. 768 * It is now protected by the FOFFSET_LOCKED flag. 769 */ 770 flagsp = &fp->f_vnread_flags; 771 if (atomic_cmpset_acq_16(flagsp, 0, FOFFSET_LOCKED)) 772 return (atomic_load_long(&fp->f_offset)); 773 774 sleepq_lock(&fp->f_vnread_flags); 775 state = atomic_load_16(flagsp); 776 for (;;) { 777 if ((state & FOFFSET_LOCKED) == 0) { 778 if (!atomic_fcmpset_acq_16(flagsp, &state, 779 FOFFSET_LOCKED)) 780 continue; 781 break; 782 } 783 if ((state & FOFFSET_LOCK_WAITING) == 0) { 784 if (!atomic_fcmpset_acq_16(flagsp, &state, 785 state | FOFFSET_LOCK_WAITING)) 786 continue; 787 } 788 DROP_GIANT(); 789 sleepq_add(&fp->f_vnread_flags, NULL, "vofflock", 0, 0); 790 sleepq_wait(&fp->f_vnread_flags, PUSER -1); 791 PICKUP_GIANT(); 792 sleepq_lock(&fp->f_vnread_flags); 793 state = atomic_load_16(flagsp); 794 } 795 res = atomic_load_long(&fp->f_offset); 796 sleepq_release(&fp->f_vnread_flags); 797 return (res); 798 } 799 800 void 801 foffset_unlock(struct file *fp, off_t val, int flags) 802 { 803 volatile short *flagsp; 804 short state; 805 806 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 807 808 if ((flags & FOF_NOUPDATE) == 0) 809 atomic_store_long(&fp->f_offset, val); 810 if ((flags & FOF_NEXTOFF_R) != 0) 811 fp->f_nextoff[UIO_READ] = val; 812 if ((flags & FOF_NEXTOFF_W) != 0) 813 fp->f_nextoff[UIO_WRITE] = val; 814 815 if ((flags & FOF_NOLOCK) != 0) 816 return; 817 818 flagsp = &fp->f_vnread_flags; 819 state = atomic_load_16(flagsp); 820 if ((state & FOFFSET_LOCK_WAITING) == 0 && 821 atomic_cmpset_rel_16(flagsp, state, 0)) 822 return; 823 824 sleepq_lock(&fp->f_vnread_flags); 825 MPASS((fp->f_vnread_flags & FOFFSET_LOCKED) != 0); 826 MPASS((fp->f_vnread_flags & FOFFSET_LOCK_WAITING) != 0); 827 fp->f_vnread_flags = 0; 828 sleepq_broadcast(&fp->f_vnread_flags, SLEEPQ_SLEEP, 0, 0); 829 sleepq_release(&fp->f_vnread_flags); 830 } 831 #else 832 off_t 833 foffset_lock(struct file *fp, int flags) 834 { 835 struct mtx *mtxp; 836 off_t res; 837 838 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 839 840 mtxp = mtx_pool_find(mtxpool_sleep, fp); 841 mtx_lock(mtxp); 842 if ((flags & FOF_NOLOCK) == 0) { 843 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 844 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 845 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 846 "vofflock", 0); 847 } 848 fp->f_vnread_flags |= FOFFSET_LOCKED; 849 } 850 res = fp->f_offset; 851 mtx_unlock(mtxp); 852 return (res); 853 } 854 855 void 856 foffset_unlock(struct file *fp, off_t val, int flags) 857 { 858 struct mtx *mtxp; 859 860 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 861 862 mtxp = mtx_pool_find(mtxpool_sleep, fp); 863 mtx_lock(mtxp); 864 if ((flags & FOF_NOUPDATE) == 0) 865 fp->f_offset = val; 866 if ((flags & FOF_NEXTOFF_R) != 0) 867 fp->f_nextoff[UIO_READ] = val; 868 if ((flags & FOF_NEXTOFF_W) != 0) 869 fp->f_nextoff[UIO_WRITE] = val; 870 if ((flags & FOF_NOLOCK) == 0) { 871 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 872 ("Lost FOFFSET_LOCKED")); 873 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 874 wakeup(&fp->f_vnread_flags); 875 fp->f_vnread_flags = 0; 876 } 877 mtx_unlock(mtxp); 878 } 879 #endif 880 881 void 882 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 883 { 884 885 if ((flags & FOF_OFFSET) == 0) 886 uio->uio_offset = foffset_lock(fp, flags); 887 } 888 889 void 890 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 891 { 892 893 if ((flags & FOF_OFFSET) == 0) 894 foffset_unlock(fp, uio->uio_offset, flags); 895 } 896 897 static int 898 get_advice(struct file *fp, struct uio *uio) 899 { 900 struct mtx *mtxp; 901 int ret; 902 903 ret = POSIX_FADV_NORMAL; 904 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG) 905 return (ret); 906 907 mtxp = mtx_pool_find(mtxpool_sleep, fp); 908 mtx_lock(mtxp); 909 if (fp->f_advice != NULL && 910 uio->uio_offset >= fp->f_advice->fa_start && 911 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 912 ret = fp->f_advice->fa_advice; 913 mtx_unlock(mtxp); 914 return (ret); 915 } 916 917 static int 918 get_write_ioflag(struct file *fp) 919 { 920 int ioflag; 921 struct mount *mp; 922 struct vnode *vp; 923 924 ioflag = 0; 925 vp = fp->f_vnode; 926 mp = atomic_load_ptr(&vp->v_mount); 927 928 if ((fp->f_flag & O_DIRECT) != 0) 929 ioflag |= IO_DIRECT; 930 931 if ((fp->f_flag & O_FSYNC) != 0 || 932 (mp != NULL && (mp->mnt_flag & MNT_SYNCHRONOUS) != 0)) 933 ioflag |= IO_SYNC; 934 935 /* 936 * For O_DSYNC we set both IO_SYNC and IO_DATASYNC, so that VOP_WRITE() 937 * or VOP_DEALLOCATE() implementations that don't understand IO_DATASYNC 938 * fall back to full O_SYNC behavior. 939 */ 940 if ((fp->f_flag & O_DSYNC) != 0) 941 ioflag |= IO_SYNC | IO_DATASYNC; 942 943 return (ioflag); 944 } 945 946 int 947 vn_read_from_obj(struct vnode *vp, struct uio *uio) 948 { 949 vm_object_t obj; 950 vm_page_t ma[io_hold_cnt + 2]; 951 off_t off, vsz; 952 ssize_t resid; 953 int error, i, j; 954 955 MPASS(uio->uio_resid <= ptoa(io_hold_cnt + 2)); 956 obj = atomic_load_ptr(&vp->v_object); 957 if (obj == NULL) 958 return (EJUSTRETURN); 959 960 /* 961 * Depends on type stability of vm_objects. 962 */ 963 vm_object_pip_add(obj, 1); 964 if ((obj->flags & OBJ_DEAD) != 0) { 965 /* 966 * Note that object might be already reused from the 967 * vnode, and the OBJ_DEAD flag cleared. This is fine, 968 * we recheck for DOOMED vnode state after all pages 969 * are busied, and retract then. 970 * 971 * But we check for OBJ_DEAD to ensure that we do not 972 * busy pages while vm_object_terminate_pages() 973 * processes the queue. 974 */ 975 error = EJUSTRETURN; 976 goto out_pip; 977 } 978 979 resid = uio->uio_resid; 980 off = uio->uio_offset; 981 for (i = 0; resid > 0; i++) { 982 MPASS(i < io_hold_cnt + 2); 983 ma[i] = vm_page_grab_unlocked(obj, atop(off), 984 VM_ALLOC_NOCREAT | VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY | 985 VM_ALLOC_NOWAIT); 986 if (ma[i] == NULL) 987 break; 988 989 /* 990 * Skip invalid pages. Valid mask can be partial only 991 * at EOF, and we clip later. 992 */ 993 if (vm_page_none_valid(ma[i])) { 994 vm_page_sunbusy(ma[i]); 995 break; 996 } 997 998 resid -= PAGE_SIZE; 999 off += PAGE_SIZE; 1000 } 1001 if (i == 0) { 1002 error = EJUSTRETURN; 1003 goto out_pip; 1004 } 1005 1006 /* 1007 * Check VIRF_DOOMED after we busied our pages. Since 1008 * vgonel() terminates the vnode' vm_object, it cannot 1009 * process past pages busied by us. 1010 */ 1011 if (VN_IS_DOOMED(vp)) { 1012 error = EJUSTRETURN; 1013 goto out; 1014 } 1015 1016 resid = PAGE_SIZE - (uio->uio_offset & PAGE_MASK) + ptoa(i - 1); 1017 if (resid > uio->uio_resid) 1018 resid = uio->uio_resid; 1019 1020 /* 1021 * Unlocked read of vnp_size is safe because truncation cannot 1022 * pass busied page. But we load vnp_size into a local 1023 * variable so that possible concurrent extension does not 1024 * break calculation. 1025 */ 1026 #if defined(__powerpc__) && !defined(__powerpc64__) 1027 vsz = obj->un_pager.vnp.vnp_size; 1028 #else 1029 vsz = atomic_load_64(&obj->un_pager.vnp.vnp_size); 1030 #endif 1031 if (uio->uio_offset >= vsz) { 1032 error = EJUSTRETURN; 1033 goto out; 1034 } 1035 if (uio->uio_offset + resid > vsz) 1036 resid = vsz - uio->uio_offset; 1037 1038 error = vn_io_fault_pgmove(ma, uio->uio_offset & PAGE_MASK, resid, uio); 1039 1040 out: 1041 for (j = 0; j < i; j++) { 1042 if (error == 0) 1043 vm_page_reference(ma[j]); 1044 vm_page_sunbusy(ma[j]); 1045 } 1046 out_pip: 1047 vm_object_pip_wakeup(obj); 1048 if (error != 0) 1049 return (error); 1050 return (uio->uio_resid == 0 ? 0 : EJUSTRETURN); 1051 } 1052 1053 /* 1054 * File table vnode read routine. 1055 */ 1056 static int 1057 vn_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1058 struct thread *td) 1059 { 1060 struct vnode *vp; 1061 off_t orig_offset; 1062 int error, ioflag; 1063 int advice; 1064 1065 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1066 uio->uio_td, td)); 1067 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1068 vp = fp->f_vnode; 1069 ioflag = 0; 1070 if (fp->f_flag & FNONBLOCK) 1071 ioflag |= IO_NDELAY; 1072 if (fp->f_flag & O_DIRECT) 1073 ioflag |= IO_DIRECT; 1074 1075 /* 1076 * Try to read from page cache. VIRF_DOOMED check is racy but 1077 * allows us to avoid unneeded work outright. 1078 */ 1079 if (vn_io_pgcache_read_enable && !mac_vnode_check_read_enabled() && 1080 (vn_irflag_read(vp) & (VIRF_DOOMED | VIRF_PGREAD)) == VIRF_PGREAD) { 1081 error = VOP_READ_PGCACHE(vp, uio, ioflag, fp->f_cred); 1082 if (error == 0) { 1083 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1084 return (0); 1085 } 1086 if (error != EJUSTRETURN) 1087 return (error); 1088 } 1089 1090 advice = get_advice(fp, uio); 1091 vn_lock(vp, LK_SHARED | LK_RETRY); 1092 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 /* Disable read-ahead for random I/O. */ 1101 break; 1102 } 1103 orig_offset = uio->uio_offset; 1104 1105 #ifdef MAC 1106 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 1107 if (error == 0) 1108 #endif 1109 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 1110 fp->f_nextoff[UIO_READ] = uio->uio_offset; 1111 VOP_UNLOCK(vp); 1112 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1113 orig_offset != uio->uio_offset) 1114 /* 1115 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1116 * for the backing file after a POSIX_FADV_NOREUSE 1117 * read(2). 1118 */ 1119 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1120 POSIX_FADV_DONTNEED); 1121 return (error); 1122 } 1123 1124 /* 1125 * File table vnode write routine. 1126 */ 1127 static int 1128 vn_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, 1129 struct thread *td) 1130 { 1131 struct vnode *vp; 1132 struct mount *mp; 1133 off_t orig_offset; 1134 int error, ioflag; 1135 int advice; 1136 bool need_finished_write; 1137 1138 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 1139 uio->uio_td, td)); 1140 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 1141 vp = fp->f_vnode; 1142 if (vp->v_type == VREG) 1143 bwillwrite(); 1144 ioflag = IO_UNIT; 1145 if (vp->v_type == VREG && (fp->f_flag & O_APPEND) != 0) 1146 ioflag |= IO_APPEND; 1147 if ((fp->f_flag & FNONBLOCK) != 0) 1148 ioflag |= IO_NDELAY; 1149 ioflag |= get_write_ioflag(fp); 1150 1151 mp = NULL; 1152 need_finished_write = false; 1153 if (vp->v_type != VCHR) { 1154 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 1155 if (error != 0) 1156 goto unlock; 1157 need_finished_write = true; 1158 } 1159 1160 advice = get_advice(fp, uio); 1161 1162 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 1163 switch (advice) { 1164 case POSIX_FADV_NORMAL: 1165 case POSIX_FADV_SEQUENTIAL: 1166 case POSIX_FADV_NOREUSE: 1167 ioflag |= sequential_heuristic(uio, fp); 1168 break; 1169 case POSIX_FADV_RANDOM: 1170 /* XXX: Is this correct? */ 1171 break; 1172 } 1173 orig_offset = uio->uio_offset; 1174 1175 #ifdef MAC 1176 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1177 if (error == 0) 1178 #endif 1179 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 1180 fp->f_nextoff[UIO_WRITE] = uio->uio_offset; 1181 VOP_UNLOCK(vp); 1182 if (need_finished_write) 1183 vn_finished_write(mp); 1184 if (error == 0 && advice == POSIX_FADV_NOREUSE && 1185 orig_offset != uio->uio_offset) 1186 /* 1187 * Use POSIX_FADV_DONTNEED to flush pages and buffers 1188 * for the backing file after a POSIX_FADV_NOREUSE 1189 * write(2). 1190 */ 1191 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1, 1192 POSIX_FADV_DONTNEED); 1193 unlock: 1194 return (error); 1195 } 1196 1197 /* 1198 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 1199 * prevent the following deadlock: 1200 * 1201 * Assume that the thread A reads from the vnode vp1 into userspace 1202 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 1203 * currently not resident, then system ends up with the call chain 1204 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 1205 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 1206 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 1207 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 1208 * backed by the pages of vnode vp1, and some page in buf2 is not 1209 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 1210 * 1211 * To prevent the lock order reversal and deadlock, vn_io_fault() does 1212 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 1213 * Instead, it first tries to do the whole range i/o with pagefaults 1214 * disabled. If all pages in the i/o buffer are resident and mapped, 1215 * VOP will succeed (ignoring the genuine filesystem errors). 1216 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 1217 * i/o in chunks, with all pages in the chunk prefaulted and held 1218 * using vm_fault_quick_hold_pages(). 1219 * 1220 * Filesystems using this deadlock avoidance scheme should use the 1221 * array of the held pages from uio, saved in the curthread->td_ma, 1222 * instead of doing uiomove(). A helper function 1223 * vn_io_fault_uiomove() converts uiomove request into 1224 * uiomove_fromphys() over td_ma array. 1225 * 1226 * Since vnode locks do not cover the whole i/o anymore, rangelocks 1227 * make the current i/o request atomic with respect to other i/os and 1228 * truncations. 1229 */ 1230 1231 /* 1232 * Decode vn_io_fault_args and perform the corresponding i/o. 1233 */ 1234 static int 1235 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 1236 struct thread *td) 1237 { 1238 int error, save; 1239 1240 error = 0; 1241 save = vm_fault_disable_pagefaults(); 1242 switch (args->kind) { 1243 case VN_IO_FAULT_FOP: 1244 error = (args->args.fop_args.doio)(args->args.fop_args.fp, 1245 uio, args->cred, args->flags, td); 1246 break; 1247 case VN_IO_FAULT_VOP: 1248 if (uio->uio_rw == UIO_READ) { 1249 error = VOP_READ(args->args.vop_args.vp, uio, 1250 args->flags, args->cred); 1251 } else if (uio->uio_rw == UIO_WRITE) { 1252 error = VOP_WRITE(args->args.vop_args.vp, uio, 1253 args->flags, args->cred); 1254 } 1255 break; 1256 default: 1257 panic("vn_io_fault_doio: unknown kind of io %d %d", 1258 args->kind, uio->uio_rw); 1259 } 1260 vm_fault_enable_pagefaults(save); 1261 return (error); 1262 } 1263 1264 static int 1265 vn_io_fault_touch(char *base, const struct uio *uio) 1266 { 1267 int r; 1268 1269 r = fubyte(base); 1270 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 1271 return (EFAULT); 1272 return (0); 1273 } 1274 1275 static int 1276 vn_io_fault_prefault_user(const struct uio *uio) 1277 { 1278 char *base; 1279 const struct iovec *iov; 1280 size_t len; 1281 ssize_t resid; 1282 int error, i; 1283 1284 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1285 ("vn_io_fault_prefault userspace")); 1286 1287 error = i = 0; 1288 iov = uio->uio_iov; 1289 resid = uio->uio_resid; 1290 base = iov->iov_base; 1291 len = iov->iov_len; 1292 while (resid > 0) { 1293 error = vn_io_fault_touch(base, uio); 1294 if (error != 0) 1295 break; 1296 if (len < PAGE_SIZE) { 1297 if (len != 0) { 1298 error = vn_io_fault_touch(base + len - 1, uio); 1299 if (error != 0) 1300 break; 1301 resid -= len; 1302 } 1303 if (++i >= uio->uio_iovcnt) 1304 break; 1305 iov = uio->uio_iov + i; 1306 base = iov->iov_base; 1307 len = iov->iov_len; 1308 } else { 1309 len -= PAGE_SIZE; 1310 base += PAGE_SIZE; 1311 resid -= PAGE_SIZE; 1312 } 1313 } 1314 return (error); 1315 } 1316 1317 /* 1318 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1319 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1320 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1321 * into args and call vn_io_fault1() to handle faults during the user 1322 * mode buffer accesses. 1323 */ 1324 static int 1325 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1326 struct thread *td) 1327 { 1328 vm_page_t ma[io_hold_cnt + 2]; 1329 struct uio *uio_clone, short_uio; 1330 struct iovec short_iovec[1]; 1331 vm_page_t *prev_td_ma; 1332 vm_prot_t prot; 1333 vm_offset_t addr, end; 1334 size_t len, resid; 1335 ssize_t adv; 1336 int error, cnt, saveheld, prev_td_ma_cnt; 1337 1338 if (vn_io_fault_prefault) { 1339 error = vn_io_fault_prefault_user(uio); 1340 if (error != 0) 1341 return (error); /* Or ignore ? */ 1342 } 1343 1344 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1345 1346 /* 1347 * The UFS follows IO_UNIT directive and replays back both 1348 * uio_offset and uio_resid if an error is encountered during the 1349 * operation. But, since the iovec may be already advanced, 1350 * uio is still in an inconsistent state. 1351 * 1352 * Cache a copy of the original uio, which is advanced to the redo 1353 * point using UIO_NOCOPY below. 1354 */ 1355 uio_clone = cloneuio(uio); 1356 resid = uio->uio_resid; 1357 1358 short_uio.uio_segflg = UIO_USERSPACE; 1359 short_uio.uio_rw = uio->uio_rw; 1360 short_uio.uio_td = uio->uio_td; 1361 1362 error = vn_io_fault_doio(args, uio, td); 1363 if (error != EFAULT) 1364 goto out; 1365 1366 atomic_add_long(&vn_io_faults_cnt, 1); 1367 uio_clone->uio_segflg = UIO_NOCOPY; 1368 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1369 uio_clone->uio_segflg = uio->uio_segflg; 1370 1371 saveheld = curthread_pflags_set(TDP_UIOHELD); 1372 prev_td_ma = td->td_ma; 1373 prev_td_ma_cnt = td->td_ma_cnt; 1374 1375 while (uio_clone->uio_resid != 0) { 1376 len = uio_clone->uio_iov->iov_len; 1377 if (len == 0) { 1378 KASSERT(uio_clone->uio_iovcnt >= 1, 1379 ("iovcnt underflow")); 1380 uio_clone->uio_iov++; 1381 uio_clone->uio_iovcnt--; 1382 continue; 1383 } 1384 if (len > ptoa(io_hold_cnt)) 1385 len = ptoa(io_hold_cnt); 1386 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1387 end = round_page(addr + len); 1388 if (end < addr) { 1389 error = EFAULT; 1390 break; 1391 } 1392 /* 1393 * A perfectly misaligned address and length could cause 1394 * both the start and the end of the chunk to use partial 1395 * page. +2 accounts for such a situation. 1396 */ 1397 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1398 addr, len, prot, ma, io_hold_cnt + 2); 1399 if (cnt == -1) { 1400 error = EFAULT; 1401 break; 1402 } 1403 short_uio.uio_iov = &short_iovec[0]; 1404 short_iovec[0].iov_base = (void *)addr; 1405 short_uio.uio_iovcnt = 1; 1406 short_uio.uio_resid = short_iovec[0].iov_len = len; 1407 short_uio.uio_offset = uio_clone->uio_offset; 1408 td->td_ma = ma; 1409 td->td_ma_cnt = cnt; 1410 1411 error = vn_io_fault_doio(args, &short_uio, td); 1412 vm_page_unhold_pages(ma, cnt); 1413 adv = len - short_uio.uio_resid; 1414 1415 uio_clone->uio_iov->iov_base = 1416 (char *)uio_clone->uio_iov->iov_base + adv; 1417 uio_clone->uio_iov->iov_len -= adv; 1418 uio_clone->uio_resid -= adv; 1419 uio_clone->uio_offset += adv; 1420 1421 uio->uio_resid -= adv; 1422 uio->uio_offset += adv; 1423 1424 if (error != 0 || adv == 0) 1425 break; 1426 } 1427 td->td_ma = prev_td_ma; 1428 td->td_ma_cnt = prev_td_ma_cnt; 1429 curthread_pflags_restore(saveheld); 1430 out: 1431 free(uio_clone, M_IOV); 1432 return (error); 1433 } 1434 1435 static int 1436 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1437 int flags, struct thread *td) 1438 { 1439 fo_rdwr_t *doio; 1440 struct vnode *vp; 1441 void *rl_cookie; 1442 struct vn_io_fault_args args; 1443 int error; 1444 bool do_io_fault, do_rangelock; 1445 1446 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1447 vp = fp->f_vnode; 1448 1449 /* 1450 * The ability to read(2) on a directory has historically been 1451 * allowed for all users, but this can and has been the source of 1452 * at least one security issue in the past. As such, it is now hidden 1453 * away behind a sysctl for those that actually need it to use it, and 1454 * restricted to root when it's turned on to make it relatively safe to 1455 * leave on for longer sessions of need. 1456 */ 1457 if (vp->v_type == VDIR) { 1458 KASSERT(uio->uio_rw == UIO_READ, 1459 ("illegal write attempted on a directory")); 1460 if (!vfs_allow_read_dir) 1461 return (EISDIR); 1462 if ((error = priv_check(td, PRIV_VFS_READ_DIR)) != 0) 1463 return (EISDIR); 1464 } 1465 1466 do_io_fault = do_vn_io_fault(vp, uio); 1467 do_rangelock = do_io_fault || (vn_irflag_read(vp) & VIRF_PGREAD) != 0; 1468 foffset_lock_uio(fp, uio, flags); 1469 if (do_rangelock) { 1470 if (uio->uio_rw == UIO_READ) { 1471 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1472 uio->uio_offset + uio->uio_resid); 1473 } else if ((fp->f_flag & O_APPEND) != 0 || 1474 (flags & FOF_OFFSET) == 0) { 1475 /* For appenders, punt and lock the whole range. */ 1476 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1477 } else { 1478 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1479 uio->uio_offset + uio->uio_resid); 1480 } 1481 } 1482 if (do_io_fault) { 1483 args.kind = VN_IO_FAULT_FOP; 1484 args.args.fop_args.fp = fp; 1485 args.args.fop_args.doio = doio; 1486 args.cred = active_cred; 1487 args.flags = flags | FOF_OFFSET; 1488 error = vn_io_fault1(vp, uio, &args, td); 1489 } else { 1490 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1491 } 1492 if (do_rangelock) 1493 vn_rangelock_unlock(vp, rl_cookie); 1494 foffset_unlock_uio(fp, uio, flags); 1495 return (error); 1496 } 1497 1498 /* 1499 * Helper function to perform the requested uiomove operation using 1500 * the held pages for io->uio_iov[0].iov_base buffer instead of 1501 * copyin/copyout. Access to the pages with uiomove_fromphys() 1502 * instead of iov_base prevents page faults that could occur due to 1503 * pmap_collect() invalidating the mapping created by 1504 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1505 * object cleanup revoking the write access from page mappings. 1506 * 1507 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1508 * instead of plain uiomove(). 1509 */ 1510 int 1511 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1512 { 1513 struct uio transp_uio; 1514 struct iovec transp_iov[1]; 1515 struct thread *td; 1516 size_t adv; 1517 int error, pgadv; 1518 1519 td = curthread; 1520 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1521 uio->uio_segflg != UIO_USERSPACE) 1522 return (uiomove(data, xfersize, uio)); 1523 1524 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1525 transp_iov[0].iov_base = data; 1526 transp_uio.uio_iov = &transp_iov[0]; 1527 transp_uio.uio_iovcnt = 1; 1528 if (xfersize > uio->uio_resid) 1529 xfersize = uio->uio_resid; 1530 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1531 transp_uio.uio_offset = 0; 1532 transp_uio.uio_segflg = UIO_SYSSPACE; 1533 /* 1534 * Since transp_iov points to data, and td_ma page array 1535 * corresponds to original uio->uio_iov, we need to invert the 1536 * direction of the i/o operation as passed to 1537 * uiomove_fromphys(). 1538 */ 1539 switch (uio->uio_rw) { 1540 case UIO_WRITE: 1541 transp_uio.uio_rw = UIO_READ; 1542 break; 1543 case UIO_READ: 1544 transp_uio.uio_rw = UIO_WRITE; 1545 break; 1546 } 1547 transp_uio.uio_td = uio->uio_td; 1548 error = uiomove_fromphys(td->td_ma, 1549 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1550 xfersize, &transp_uio); 1551 adv = xfersize - transp_uio.uio_resid; 1552 pgadv = 1553 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1554 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1555 td->td_ma += pgadv; 1556 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1557 pgadv)); 1558 td->td_ma_cnt -= pgadv; 1559 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1560 uio->uio_iov->iov_len -= adv; 1561 uio->uio_resid -= adv; 1562 uio->uio_offset += adv; 1563 return (error); 1564 } 1565 1566 int 1567 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1568 struct uio *uio) 1569 { 1570 struct thread *td; 1571 vm_offset_t iov_base; 1572 int cnt, pgadv; 1573 1574 td = curthread; 1575 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1576 uio->uio_segflg != UIO_USERSPACE) 1577 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1578 1579 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1580 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1581 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1582 switch (uio->uio_rw) { 1583 case UIO_WRITE: 1584 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1585 offset, cnt); 1586 break; 1587 case UIO_READ: 1588 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1589 cnt); 1590 break; 1591 } 1592 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1593 td->td_ma += pgadv; 1594 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1595 pgadv)); 1596 td->td_ma_cnt -= pgadv; 1597 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1598 uio->uio_iov->iov_len -= cnt; 1599 uio->uio_resid -= cnt; 1600 uio->uio_offset += cnt; 1601 return (0); 1602 } 1603 1604 /* 1605 * File table truncate routine. 1606 */ 1607 static int 1608 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1609 struct thread *td) 1610 { 1611 struct mount *mp; 1612 struct vnode *vp; 1613 void *rl_cookie; 1614 int error; 1615 1616 vp = fp->f_vnode; 1617 1618 retry: 1619 /* 1620 * Lock the whole range for truncation. Otherwise split i/o 1621 * might happen partly before and partly after the truncation. 1622 */ 1623 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1624 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 1625 if (error) 1626 goto out1; 1627 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1628 AUDIT_ARG_VNODE1(vp); 1629 if (vp->v_type == VDIR) { 1630 error = EISDIR; 1631 goto out; 1632 } 1633 #ifdef MAC 1634 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1635 if (error) 1636 goto out; 1637 #endif 1638 error = vn_truncate_locked(vp, length, (fp->f_flag & O_FSYNC) != 0, 1639 fp->f_cred); 1640 out: 1641 VOP_UNLOCK(vp); 1642 vn_finished_write(mp); 1643 out1: 1644 vn_rangelock_unlock(vp, rl_cookie); 1645 if (error == ERELOOKUP) 1646 goto retry; 1647 return (error); 1648 } 1649 1650 /* 1651 * Truncate a file that is already locked. 1652 */ 1653 int 1654 vn_truncate_locked(struct vnode *vp, off_t length, bool sync, 1655 struct ucred *cred) 1656 { 1657 struct vattr vattr; 1658 int error; 1659 1660 error = VOP_ADD_WRITECOUNT(vp, 1); 1661 if (error == 0) { 1662 VATTR_NULL(&vattr); 1663 vattr.va_size = length; 1664 if (sync) 1665 vattr.va_vaflags |= VA_SYNC; 1666 error = VOP_SETATTR(vp, &vattr, cred); 1667 VOP_ADD_WRITECOUNT_CHECKED(vp, -1); 1668 } 1669 return (error); 1670 } 1671 1672 /* 1673 * File table vnode stat routine. 1674 */ 1675 int 1676 vn_statfile(struct file *fp, struct stat *sb, struct ucred *active_cred) 1677 { 1678 struct vnode *vp = fp->f_vnode; 1679 int error; 1680 1681 vn_lock(vp, LK_SHARED | LK_RETRY); 1682 error = VOP_STAT(vp, sb, active_cred, fp->f_cred); 1683 VOP_UNLOCK(vp); 1684 1685 return (error); 1686 } 1687 1688 /* 1689 * File table vnode ioctl routine. 1690 */ 1691 static int 1692 vn_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, 1693 struct thread *td) 1694 { 1695 struct vnode *vp; 1696 struct fiobmap2_arg *bmarg; 1697 off_t size; 1698 int error; 1699 1700 vp = fp->f_vnode; 1701 switch (vp->v_type) { 1702 case VDIR: 1703 case VREG: 1704 switch (com) { 1705 case FIONREAD: 1706 error = vn_getsize(vp, &size, active_cred); 1707 if (error == 0) 1708 *(int *)data = size - fp->f_offset; 1709 return (error); 1710 case FIOBMAP2: 1711 bmarg = (struct fiobmap2_arg *)data; 1712 vn_lock(vp, LK_SHARED | LK_RETRY); 1713 #ifdef MAC 1714 error = mac_vnode_check_read(active_cred, fp->f_cred, 1715 vp); 1716 if (error == 0) 1717 #endif 1718 error = VOP_BMAP(vp, bmarg->bn, NULL, 1719 &bmarg->bn, &bmarg->runp, &bmarg->runb); 1720 VOP_UNLOCK(vp); 1721 return (error); 1722 case FIONBIO: 1723 case FIOASYNC: 1724 return (0); 1725 default: 1726 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1727 active_cred, td)); 1728 } 1729 break; 1730 case VCHR: 1731 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1732 active_cred, td)); 1733 default: 1734 return (ENOTTY); 1735 } 1736 } 1737 1738 /* 1739 * File table vnode poll routine. 1740 */ 1741 static int 1742 vn_poll(struct file *fp, int events, struct ucred *active_cred, 1743 struct thread *td) 1744 { 1745 struct vnode *vp; 1746 int error; 1747 1748 vp = fp->f_vnode; 1749 #if defined(MAC) || defined(AUDIT) 1750 if (AUDITING_TD(td) || mac_vnode_check_poll_enabled()) { 1751 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1752 AUDIT_ARG_VNODE1(vp); 1753 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1754 VOP_UNLOCK(vp); 1755 if (error != 0) 1756 return (error); 1757 } 1758 #endif 1759 error = VOP_POLL(vp, events, fp->f_cred, td); 1760 return (error); 1761 } 1762 1763 /* 1764 * Acquire the requested lock and then check for validity. LK_RETRY 1765 * permits vn_lock to return doomed vnodes. 1766 */ 1767 static int __noinline 1768 _vn_lock_fallback(struct vnode *vp, int flags, const char *file, int line, 1769 int error) 1770 { 1771 1772 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1773 ("vn_lock: error %d incompatible with flags %#x", error, flags)); 1774 1775 if (error == 0) 1776 VNASSERT(VN_IS_DOOMED(vp), vp, ("vnode not doomed")); 1777 1778 if ((flags & LK_RETRY) == 0) { 1779 if (error == 0) { 1780 VOP_UNLOCK(vp); 1781 error = ENOENT; 1782 } 1783 return (error); 1784 } 1785 1786 /* 1787 * LK_RETRY case. 1788 * 1789 * Nothing to do if we got the lock. 1790 */ 1791 if (error == 0) 1792 return (0); 1793 1794 /* 1795 * Interlock was dropped by the call in _vn_lock. 1796 */ 1797 flags &= ~LK_INTERLOCK; 1798 do { 1799 error = VOP_LOCK1(vp, flags, file, line); 1800 } while (error != 0); 1801 return (0); 1802 } 1803 1804 int 1805 _vn_lock(struct vnode *vp, int flags, const char *file, int line) 1806 { 1807 int error; 1808 1809 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1810 ("vn_lock: no locktype (%d passed)", flags)); 1811 VNPASS(vp->v_holdcnt > 0, vp); 1812 error = VOP_LOCK1(vp, flags, file, line); 1813 if (__predict_false(error != 0 || VN_IS_DOOMED(vp))) 1814 return (_vn_lock_fallback(vp, flags, file, line, error)); 1815 return (0); 1816 } 1817 1818 /* 1819 * File table vnode close routine. 1820 */ 1821 static int 1822 vn_closefile(struct file *fp, struct thread *td) 1823 { 1824 struct vnode *vp; 1825 struct flock lf; 1826 int error; 1827 bool ref; 1828 1829 vp = fp->f_vnode; 1830 fp->f_ops = &badfileops; 1831 ref = (fp->f_flag & FHASLOCK) != 0; 1832 1833 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref); 1834 1835 if (__predict_false(ref)) { 1836 lf.l_whence = SEEK_SET; 1837 lf.l_start = 0; 1838 lf.l_len = 0; 1839 lf.l_type = F_UNLCK; 1840 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1841 vrele(vp); 1842 } 1843 return (error); 1844 } 1845 1846 /* 1847 * Preparing to start a filesystem write operation. If the operation is 1848 * permitted, then we bump the count of operations in progress and 1849 * proceed. If a suspend request is in progress, we wait until the 1850 * suspension is over, and then proceed. 1851 */ 1852 static int 1853 vn_start_write_refed(struct mount *mp, int flags, bool mplocked) 1854 { 1855 struct mount_pcpu *mpcpu; 1856 int error, mflags; 1857 1858 if (__predict_true(!mplocked) && (flags & V_XSLEEP) == 0 && 1859 vfs_op_thread_enter(mp, mpcpu)) { 1860 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 1861 vfs_mp_count_add_pcpu(mpcpu, writeopcount, 1); 1862 vfs_op_thread_exit(mp, mpcpu); 1863 return (0); 1864 } 1865 1866 if (mplocked) 1867 mtx_assert(MNT_MTX(mp), MA_OWNED); 1868 else 1869 MNT_ILOCK(mp); 1870 1871 error = 0; 1872 1873 /* 1874 * Check on status of suspension. 1875 */ 1876 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1877 mp->mnt_susp_owner != curthread) { 1878 mflags = 0; 1879 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) { 1880 if (flags & V_PCATCH) 1881 mflags |= PCATCH; 1882 } 1883 mflags |= (PUSER - 1); 1884 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1885 if ((flags & V_NOWAIT) != 0) { 1886 error = EWOULDBLOCK; 1887 goto unlock; 1888 } 1889 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1890 "suspfs", 0); 1891 if (error != 0) 1892 goto unlock; 1893 } 1894 } 1895 if ((flags & V_XSLEEP) != 0) 1896 goto unlock; 1897 mp->mnt_writeopcount++; 1898 unlock: 1899 if (error != 0 || (flags & V_XSLEEP) != 0) 1900 MNT_REL(mp); 1901 MNT_IUNLOCK(mp); 1902 return (error); 1903 } 1904 1905 int 1906 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1907 { 1908 struct mount *mp; 1909 int error; 1910 1911 KASSERT((flags & ~V_VALID_FLAGS) == 0, 1912 ("%s: invalid flags passed %d\n", __func__, flags)); 1913 1914 error = 0; 1915 /* 1916 * If a vnode is provided, get and return the mount point that 1917 * to which it will write. 1918 */ 1919 if (vp != NULL) { 1920 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1921 *mpp = NULL; 1922 if (error != EOPNOTSUPP) 1923 return (error); 1924 return (0); 1925 } 1926 } 1927 if ((mp = *mpp) == NULL) 1928 return (0); 1929 1930 /* 1931 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1932 * a vfs_ref(). 1933 * As long as a vnode is not provided we need to acquire a 1934 * refcount for the provided mountpoint too, in order to 1935 * emulate a vfs_ref(). 1936 */ 1937 if (vp == NULL) 1938 vfs_ref(mp); 1939 1940 error = vn_start_write_refed(mp, flags, false); 1941 if (error != 0 && (flags & V_NOWAIT) == 0) 1942 *mpp = NULL; 1943 return (error); 1944 } 1945 1946 /* 1947 * Secondary suspension. Used by operations such as vop_inactive 1948 * routines that are needed by the higher level functions. These 1949 * are allowed to proceed until all the higher level functions have 1950 * completed (indicated by mnt_writeopcount dropping to zero). At that 1951 * time, these operations are halted until the suspension is over. 1952 */ 1953 int 1954 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1955 { 1956 struct mount *mp; 1957 int error, mflags; 1958 1959 KASSERT((flags & (~V_VALID_FLAGS | V_XSLEEP)) == 0, 1960 ("%s: invalid flags passed %d\n", __func__, flags)); 1961 1962 retry: 1963 if (vp != NULL) { 1964 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1965 *mpp = NULL; 1966 if (error != EOPNOTSUPP) 1967 return (error); 1968 return (0); 1969 } 1970 } 1971 /* 1972 * If we are not suspended or have not yet reached suspended 1973 * mode, then let the operation proceed. 1974 */ 1975 if ((mp = *mpp) == NULL) 1976 return (0); 1977 1978 /* 1979 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1980 * a vfs_ref(). 1981 * As long as a vnode is not provided we need to acquire a 1982 * refcount for the provided mountpoint too, in order to 1983 * emulate a vfs_ref(). 1984 */ 1985 MNT_ILOCK(mp); 1986 if (vp == NULL) 1987 MNT_REF(mp); 1988 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1989 mp->mnt_secondary_writes++; 1990 mp->mnt_secondary_accwrites++; 1991 MNT_IUNLOCK(mp); 1992 return (0); 1993 } 1994 if ((flags & V_NOWAIT) != 0) { 1995 MNT_REL(mp); 1996 MNT_IUNLOCK(mp); 1997 *mpp = NULL; 1998 return (EWOULDBLOCK); 1999 } 2000 /* 2001 * Wait for the suspension to finish. 2002 */ 2003 mflags = 0; 2004 if ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0) { 2005 if ((flags & V_PCATCH) != 0) 2006 mflags |= PCATCH; 2007 } 2008 mflags |= (PUSER - 1) | PDROP; 2009 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, "suspfs", 0); 2010 vfs_rel(mp); 2011 if (error == 0) 2012 goto retry; 2013 *mpp = NULL; 2014 return (error); 2015 } 2016 2017 /* 2018 * Filesystem write operation has completed. If we are suspending and this 2019 * operation is the last one, notify the suspender that the suspension is 2020 * now in effect. 2021 */ 2022 void 2023 vn_finished_write(struct mount *mp) 2024 { 2025 struct mount_pcpu *mpcpu; 2026 int c; 2027 2028 if (mp == NULL) 2029 return; 2030 2031 if (vfs_op_thread_enter(mp, mpcpu)) { 2032 vfs_mp_count_sub_pcpu(mpcpu, writeopcount, 1); 2033 vfs_mp_count_sub_pcpu(mpcpu, ref, 1); 2034 vfs_op_thread_exit(mp, mpcpu); 2035 return; 2036 } 2037 2038 MNT_ILOCK(mp); 2039 vfs_assert_mount_counters(mp); 2040 MNT_REL(mp); 2041 c = --mp->mnt_writeopcount; 2042 if (mp->mnt_vfs_ops == 0) { 2043 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) == 0); 2044 MNT_IUNLOCK(mp); 2045 return; 2046 } 2047 if (c < 0) 2048 vfs_dump_mount_counters(mp); 2049 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && c == 0) 2050 wakeup(&mp->mnt_writeopcount); 2051 MNT_IUNLOCK(mp); 2052 } 2053 2054 /* 2055 * Filesystem secondary write operation has completed. If we are 2056 * suspending and this operation is the last one, notify the suspender 2057 * that the suspension is now in effect. 2058 */ 2059 void 2060 vn_finished_secondary_write(struct mount *mp) 2061 { 2062 if (mp == NULL) 2063 return; 2064 MNT_ILOCK(mp); 2065 MNT_REL(mp); 2066 mp->mnt_secondary_writes--; 2067 if (mp->mnt_secondary_writes < 0) 2068 panic("vn_finished_secondary_write: neg cnt"); 2069 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 2070 mp->mnt_secondary_writes <= 0) 2071 wakeup(&mp->mnt_secondary_writes); 2072 MNT_IUNLOCK(mp); 2073 } 2074 2075 /* 2076 * Request a filesystem to suspend write operations. 2077 */ 2078 int 2079 vfs_write_suspend(struct mount *mp, int flags) 2080 { 2081 int error; 2082 2083 vfs_op_enter(mp); 2084 2085 MNT_ILOCK(mp); 2086 vfs_assert_mount_counters(mp); 2087 if (mp->mnt_susp_owner == curthread) { 2088 vfs_op_exit_locked(mp); 2089 MNT_IUNLOCK(mp); 2090 return (EALREADY); 2091 } 2092 while (mp->mnt_kern_flag & MNTK_SUSPEND) 2093 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 2094 2095 /* 2096 * Unmount holds a write reference on the mount point. If we 2097 * own busy reference and drain for writers, we deadlock with 2098 * the reference draining in the unmount path. Callers of 2099 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 2100 * vfs_busy() reference is owned and caller is not in the 2101 * unmount context. 2102 */ 2103 if ((flags & VS_SKIP_UNMOUNT) != 0 && 2104 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 2105 vfs_op_exit_locked(mp); 2106 MNT_IUNLOCK(mp); 2107 return (EBUSY); 2108 } 2109 2110 mp->mnt_kern_flag |= MNTK_SUSPEND; 2111 mp->mnt_susp_owner = curthread; 2112 if (mp->mnt_writeopcount > 0) 2113 (void) msleep(&mp->mnt_writeopcount, 2114 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 2115 else 2116 MNT_IUNLOCK(mp); 2117 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) { 2118 vfs_write_resume(mp, 0); 2119 /* vfs_write_resume does vfs_op_exit() for us */ 2120 } 2121 return (error); 2122 } 2123 2124 /* 2125 * Request a filesystem to resume write operations. 2126 */ 2127 void 2128 vfs_write_resume(struct mount *mp, int flags) 2129 { 2130 2131 MNT_ILOCK(mp); 2132 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 2133 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 2134 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 2135 MNTK_SUSPENDED); 2136 mp->mnt_susp_owner = NULL; 2137 wakeup(&mp->mnt_writeopcount); 2138 wakeup(&mp->mnt_flag); 2139 curthread->td_pflags &= ~TDP_IGNSUSP; 2140 if ((flags & VR_START_WRITE) != 0) { 2141 MNT_REF(mp); 2142 mp->mnt_writeopcount++; 2143 } 2144 MNT_IUNLOCK(mp); 2145 if ((flags & VR_NO_SUSPCLR) == 0) 2146 VFS_SUSP_CLEAN(mp); 2147 vfs_op_exit(mp); 2148 } else if ((flags & VR_START_WRITE) != 0) { 2149 MNT_REF(mp); 2150 vn_start_write_refed(mp, 0, true); 2151 } else { 2152 MNT_IUNLOCK(mp); 2153 } 2154 } 2155 2156 /* 2157 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 2158 * methods. 2159 */ 2160 int 2161 vfs_write_suspend_umnt(struct mount *mp) 2162 { 2163 int error; 2164 2165 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 2166 ("vfs_write_suspend_umnt: recursed")); 2167 2168 /* dounmount() already called vn_start_write(). */ 2169 for (;;) { 2170 vn_finished_write(mp); 2171 error = vfs_write_suspend(mp, 0); 2172 if (error != 0) { 2173 vn_start_write(NULL, &mp, V_WAIT); 2174 return (error); 2175 } 2176 MNT_ILOCK(mp); 2177 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 2178 break; 2179 MNT_IUNLOCK(mp); 2180 vn_start_write(NULL, &mp, V_WAIT); 2181 } 2182 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 2183 wakeup(&mp->mnt_flag); 2184 MNT_IUNLOCK(mp); 2185 curthread->td_pflags |= TDP_IGNSUSP; 2186 return (0); 2187 } 2188 2189 /* 2190 * Implement kqueues for files by translating it to vnode operation. 2191 */ 2192 static int 2193 vn_kqfilter(struct file *fp, struct knote *kn) 2194 { 2195 2196 return (VOP_KQFILTER(fp->f_vnode, kn)); 2197 } 2198 2199 int 2200 vn_kqfilter_opath(struct file *fp, struct knote *kn) 2201 { 2202 if ((fp->f_flag & FKQALLOWED) == 0) 2203 return (EBADF); 2204 return (vn_kqfilter(fp, kn)); 2205 } 2206 2207 /* 2208 * Simplified in-kernel wrapper calls for extended attribute access. 2209 * Both calls pass in a NULL credential, authorizing as "kernel" access. 2210 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 2211 */ 2212 int 2213 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 2214 const char *attrname, int *buflen, char *buf, struct thread *td) 2215 { 2216 struct uio auio; 2217 struct iovec iov; 2218 int error; 2219 2220 iov.iov_len = *buflen; 2221 iov.iov_base = buf; 2222 2223 auio.uio_iov = &iov; 2224 auio.uio_iovcnt = 1; 2225 auio.uio_rw = UIO_READ; 2226 auio.uio_segflg = UIO_SYSSPACE; 2227 auio.uio_td = td; 2228 auio.uio_offset = 0; 2229 auio.uio_resid = *buflen; 2230 2231 if ((ioflg & IO_NODELOCKED) == 0) 2232 vn_lock(vp, LK_SHARED | LK_RETRY); 2233 2234 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2235 2236 /* authorize attribute retrieval as kernel */ 2237 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2238 td); 2239 2240 if ((ioflg & IO_NODELOCKED) == 0) 2241 VOP_UNLOCK(vp); 2242 2243 if (error == 0) { 2244 *buflen = *buflen - auio.uio_resid; 2245 } 2246 2247 return (error); 2248 } 2249 2250 /* 2251 * XXX failure mode if partially written? 2252 */ 2253 int 2254 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2255 const char *attrname, int buflen, char *buf, struct thread *td) 2256 { 2257 struct uio auio; 2258 struct iovec iov; 2259 struct mount *mp; 2260 int error; 2261 2262 iov.iov_len = buflen; 2263 iov.iov_base = buf; 2264 2265 auio.uio_iov = &iov; 2266 auio.uio_iovcnt = 1; 2267 auio.uio_rw = UIO_WRITE; 2268 auio.uio_segflg = UIO_SYSSPACE; 2269 auio.uio_td = td; 2270 auio.uio_offset = 0; 2271 auio.uio_resid = buflen; 2272 2273 if ((ioflg & IO_NODELOCKED) == 0) { 2274 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2275 return (error); 2276 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2277 } 2278 2279 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2280 2281 /* authorize attribute setting as kernel */ 2282 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2283 2284 if ((ioflg & IO_NODELOCKED) == 0) { 2285 vn_finished_write(mp); 2286 VOP_UNLOCK(vp); 2287 } 2288 2289 return (error); 2290 } 2291 2292 int 2293 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2294 const char *attrname, struct thread *td) 2295 { 2296 struct mount *mp; 2297 int error; 2298 2299 if ((ioflg & IO_NODELOCKED) == 0) { 2300 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2301 return (error); 2302 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2303 } 2304 2305 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2306 2307 /* authorize attribute removal as kernel */ 2308 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2309 if (error == EOPNOTSUPP) 2310 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2311 NULL, td); 2312 2313 if ((ioflg & IO_NODELOCKED) == 0) { 2314 vn_finished_write(mp); 2315 VOP_UNLOCK(vp); 2316 } 2317 2318 return (error); 2319 } 2320 2321 static int 2322 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2323 struct vnode **rvp) 2324 { 2325 2326 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2327 } 2328 2329 int 2330 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2331 { 2332 2333 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2334 lkflags, rvp)); 2335 } 2336 2337 int 2338 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2339 int lkflags, struct vnode **rvp) 2340 { 2341 struct mount *mp; 2342 int ltype, error; 2343 2344 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2345 mp = vp->v_mount; 2346 ltype = VOP_ISLOCKED(vp); 2347 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2348 ("vn_vget_ino: vp not locked")); 2349 error = vfs_busy(mp, MBF_NOWAIT); 2350 if (error != 0) { 2351 vfs_ref(mp); 2352 VOP_UNLOCK(vp); 2353 error = vfs_busy(mp, 0); 2354 vn_lock(vp, ltype | LK_RETRY); 2355 vfs_rel(mp); 2356 if (error != 0) 2357 return (ENOENT); 2358 if (VN_IS_DOOMED(vp)) { 2359 vfs_unbusy(mp); 2360 return (ENOENT); 2361 } 2362 } 2363 VOP_UNLOCK(vp); 2364 error = alloc(mp, alloc_arg, lkflags, rvp); 2365 vfs_unbusy(mp); 2366 if (error != 0 || *rvp != vp) 2367 vn_lock(vp, ltype | LK_RETRY); 2368 if (VN_IS_DOOMED(vp)) { 2369 if (error == 0) { 2370 if (*rvp == vp) 2371 vunref(vp); 2372 else 2373 vput(*rvp); 2374 } 2375 error = ENOENT; 2376 } 2377 return (error); 2378 } 2379 2380 static void 2381 vn_send_sigxfsz(struct proc *p) 2382 { 2383 PROC_LOCK(p); 2384 kern_psignal(p, SIGXFSZ); 2385 PROC_UNLOCK(p); 2386 } 2387 2388 int 2389 vn_rlimit_trunc(u_quad_t size, struct thread *td) 2390 { 2391 if (size <= lim_cur(td, RLIMIT_FSIZE)) 2392 return (0); 2393 vn_send_sigxfsz(td->td_proc); 2394 return (EFBIG); 2395 } 2396 2397 static int 2398 vn_rlimit_fsizex1(const struct vnode *vp, struct uio *uio, off_t maxfsz, 2399 bool adj, struct thread *td) 2400 { 2401 off_t lim; 2402 bool ktr_write; 2403 2404 if (vp->v_type != VREG) 2405 return (0); 2406 2407 /* 2408 * Handle file system maximum file size. 2409 */ 2410 if (maxfsz != 0 && uio->uio_offset + uio->uio_resid > maxfsz) { 2411 if (!adj || uio->uio_offset >= maxfsz) 2412 return (EFBIG); 2413 uio->uio_resid = maxfsz - uio->uio_offset; 2414 } 2415 2416 /* 2417 * This is kernel write (e.g. vnode_pager) or accounting 2418 * write, ignore limit. 2419 */ 2420 if (td == NULL || (td->td_pflags2 & TDP2_ACCT) != 0) 2421 return (0); 2422 2423 /* 2424 * Calculate file size limit. 2425 */ 2426 ktr_write = (td->td_pflags & TDP_INKTRACE) != 0; 2427 lim = __predict_false(ktr_write) ? td->td_ktr_io_lim : 2428 lim_cur(td, RLIMIT_FSIZE); 2429 2430 /* 2431 * Is the limit reached? 2432 */ 2433 if (__predict_true((uoff_t)uio->uio_offset + uio->uio_resid <= lim)) 2434 return (0); 2435 2436 /* 2437 * Prepared filesystems can handle writes truncated to the 2438 * file size limit. 2439 */ 2440 if (adj && (uoff_t)uio->uio_offset < lim) { 2441 uio->uio_resid = lim - (uoff_t)uio->uio_offset; 2442 return (0); 2443 } 2444 2445 if (!ktr_write || ktr_filesize_limit_signal) 2446 vn_send_sigxfsz(td->td_proc); 2447 return (EFBIG); 2448 } 2449 2450 /* 2451 * Helper for VOP_WRITE() implementations, the common code to 2452 * handle maximum supported file size on the filesystem, and 2453 * RLIMIT_FSIZE, except for special writes from accounting subsystem 2454 * and ktrace. 2455 * 2456 * For maximum file size (maxfsz argument): 2457 * - return EFBIG if uio_offset is beyond it 2458 * - otherwise, clamp uio_resid if write would extend file beyond maxfsz. 2459 * 2460 * For RLIMIT_FSIZE: 2461 * - return EFBIG and send SIGXFSZ if uio_offset is beyond the limit 2462 * - otherwise, clamp uio_resid if write would extend file beyond limit. 2463 * 2464 * If clamping occured, the adjustment for uio_resid is stored in 2465 * *resid_adj, to be re-applied by vn_rlimit_fsizex_res() on return 2466 * from the VOP. 2467 */ 2468 int 2469 vn_rlimit_fsizex(const struct vnode *vp, struct uio *uio, off_t maxfsz, 2470 ssize_t *resid_adj, struct thread *td) 2471 { 2472 ssize_t resid_orig; 2473 int error; 2474 bool adj; 2475 2476 resid_orig = uio->uio_resid; 2477 adj = resid_adj != NULL; 2478 error = vn_rlimit_fsizex1(vp, uio, maxfsz, adj, td); 2479 if (adj) 2480 *resid_adj = resid_orig - uio->uio_resid; 2481 return (error); 2482 } 2483 2484 void 2485 vn_rlimit_fsizex_res(struct uio *uio, ssize_t resid_adj) 2486 { 2487 uio->uio_resid += resid_adj; 2488 } 2489 2490 int 2491 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2492 struct thread *td) 2493 { 2494 return (vn_rlimit_fsizex(vp, __DECONST(struct uio *, uio), 0, NULL, 2495 td)); 2496 } 2497 2498 int 2499 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2500 struct thread *td) 2501 { 2502 struct vnode *vp; 2503 2504 vp = fp->f_vnode; 2505 #ifdef AUDIT 2506 vn_lock(vp, LK_SHARED | LK_RETRY); 2507 AUDIT_ARG_VNODE1(vp); 2508 VOP_UNLOCK(vp); 2509 #endif 2510 return (setfmode(td, active_cred, vp, mode)); 2511 } 2512 2513 int 2514 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2515 struct thread *td) 2516 { 2517 struct vnode *vp; 2518 2519 vp = fp->f_vnode; 2520 #ifdef AUDIT 2521 vn_lock(vp, LK_SHARED | LK_RETRY); 2522 AUDIT_ARG_VNODE1(vp); 2523 VOP_UNLOCK(vp); 2524 #endif 2525 return (setfown(td, active_cred, vp, uid, gid)); 2526 } 2527 2528 /* 2529 * Remove pages in the range ["start", "end") from the vnode's VM object. If 2530 * "end" is 0, then the range extends to the end of the object. 2531 */ 2532 void 2533 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2534 { 2535 vm_object_t object; 2536 2537 if ((object = vp->v_object) == NULL) 2538 return; 2539 VM_OBJECT_WLOCK(object); 2540 vm_object_page_remove(object, start, end, 0); 2541 VM_OBJECT_WUNLOCK(object); 2542 } 2543 2544 /* 2545 * Like vn_pages_remove(), but skips invalid pages, which by definition are not 2546 * mapped into any process' address space. Filesystems may use this in 2547 * preference to vn_pages_remove() to avoid blocking on pages busied in 2548 * preparation for a VOP_GETPAGES. 2549 */ 2550 void 2551 vn_pages_remove_valid(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2552 { 2553 vm_object_t object; 2554 2555 if ((object = vp->v_object) == NULL) 2556 return; 2557 VM_OBJECT_WLOCK(object); 2558 vm_object_page_remove(object, start, end, OBJPR_VALIDONLY); 2559 VM_OBJECT_WUNLOCK(object); 2560 } 2561 2562 int 2563 vn_bmap_seekhole_locked(struct vnode *vp, u_long cmd, off_t *off, 2564 struct ucred *cred) 2565 { 2566 vm_object_t obj; 2567 off_t size; 2568 daddr_t bn, bnp; 2569 uint64_t bsize; 2570 off_t noff; 2571 int error; 2572 2573 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2574 ("%s: Wrong command %lu", __func__, cmd)); 2575 ASSERT_VOP_ELOCKED(vp, "vn_bmap_seekhole_locked"); 2576 2577 if (vp->v_type != VREG) { 2578 error = ENOTTY; 2579 goto out; 2580 } 2581 error = vn_getsize_locked(vp, &size, cred); 2582 if (error != 0) 2583 goto out; 2584 noff = *off; 2585 if (noff < 0 || noff >= size) { 2586 error = ENXIO; 2587 goto out; 2588 } 2589 2590 /* See the comment in ufs_bmap_seekdata(). */ 2591 obj = vp->v_object; 2592 if (obj != NULL) { 2593 VM_OBJECT_WLOCK(obj); 2594 vm_object_page_clean(obj, 0, 0, OBJPC_SYNC); 2595 VM_OBJECT_WUNLOCK(obj); 2596 } 2597 2598 bsize = vp->v_mount->mnt_stat.f_iosize; 2599 for (bn = noff / bsize; noff < size; bn++, noff += bsize - 2600 noff % bsize) { 2601 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2602 if (error == EOPNOTSUPP) { 2603 error = ENOTTY; 2604 goto out; 2605 } 2606 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2607 (bnp != -1 && cmd == FIOSEEKDATA)) { 2608 noff = bn * bsize; 2609 if (noff < *off) 2610 noff = *off; 2611 goto out; 2612 } 2613 } 2614 if (noff > size) 2615 noff = size; 2616 /* noff == size. There is an implicit hole at the end of file. */ 2617 if (cmd == FIOSEEKDATA) 2618 error = ENXIO; 2619 out: 2620 if (error == 0) 2621 *off = noff; 2622 return (error); 2623 } 2624 2625 int 2626 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2627 { 2628 int error; 2629 2630 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2631 ("%s: Wrong command %lu", __func__, cmd)); 2632 2633 if (vn_lock(vp, LK_EXCLUSIVE) != 0) 2634 return (EBADF); 2635 error = vn_bmap_seekhole_locked(vp, cmd, off, cred); 2636 VOP_UNLOCK(vp); 2637 return (error); 2638 } 2639 2640 int 2641 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2642 { 2643 struct ucred *cred; 2644 struct vnode *vp; 2645 off_t foffset, fsize, size; 2646 int error, noneg; 2647 2648 cred = td->td_ucred; 2649 vp = fp->f_vnode; 2650 foffset = foffset_lock(fp, 0); 2651 noneg = (vp->v_type != VCHR); 2652 error = 0; 2653 switch (whence) { 2654 case L_INCR: 2655 if (noneg && 2656 (foffset < 0 || 2657 (offset > 0 && foffset > OFF_MAX - offset))) { 2658 error = EOVERFLOW; 2659 break; 2660 } 2661 offset += foffset; 2662 break; 2663 case L_XTND: 2664 error = vn_getsize(vp, &fsize, cred); 2665 if (error != 0) 2666 break; 2667 2668 /* 2669 * If the file references a disk device, then fetch 2670 * the media size and use that to determine the ending 2671 * offset. 2672 */ 2673 if (fsize == 0 && vp->v_type == VCHR && 2674 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2675 fsize = size; 2676 if (noneg && offset > 0 && fsize > OFF_MAX - offset) { 2677 error = EOVERFLOW; 2678 break; 2679 } 2680 offset += fsize; 2681 break; 2682 case L_SET: 2683 break; 2684 case SEEK_DATA: 2685 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2686 if (error == ENOTTY) 2687 error = EINVAL; 2688 break; 2689 case SEEK_HOLE: 2690 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2691 if (error == ENOTTY) 2692 error = EINVAL; 2693 break; 2694 default: 2695 error = EINVAL; 2696 } 2697 if (error == 0 && noneg && offset < 0) 2698 error = EINVAL; 2699 if (error != 0) 2700 goto drop; 2701 VFS_KNOTE_UNLOCKED(vp, 0); 2702 td->td_uretoff.tdu_off = offset; 2703 drop: 2704 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2705 return (error); 2706 } 2707 2708 int 2709 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2710 struct thread *td) 2711 { 2712 int error; 2713 2714 /* 2715 * Grant permission if the caller is the owner of the file, or 2716 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2717 * on the file. If the time pointer is null, then write 2718 * permission on the file is also sufficient. 2719 * 2720 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2721 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2722 * will be allowed to set the times [..] to the current 2723 * server time. 2724 */ 2725 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2726 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2727 error = VOP_ACCESS(vp, VWRITE, cred, td); 2728 return (error); 2729 } 2730 2731 int 2732 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2733 { 2734 struct vnode *vp; 2735 int error; 2736 2737 if (fp->f_type == DTYPE_FIFO) 2738 kif->kf_type = KF_TYPE_FIFO; 2739 else 2740 kif->kf_type = KF_TYPE_VNODE; 2741 vp = fp->f_vnode; 2742 vref(vp); 2743 FILEDESC_SUNLOCK(fdp); 2744 error = vn_fill_kinfo_vnode(vp, kif); 2745 vrele(vp); 2746 FILEDESC_SLOCK(fdp); 2747 return (error); 2748 } 2749 2750 static inline void 2751 vn_fill_junk(struct kinfo_file *kif) 2752 { 2753 size_t len, olen; 2754 2755 /* 2756 * Simulate vn_fullpath returning changing values for a given 2757 * vp during e.g. coredump. 2758 */ 2759 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2760 olen = strlen(kif->kf_path); 2761 if (len < olen) 2762 strcpy(&kif->kf_path[len - 1], "$"); 2763 else 2764 for (; olen < len; olen++) 2765 strcpy(&kif->kf_path[olen], "A"); 2766 } 2767 2768 int 2769 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2770 { 2771 struct vattr va; 2772 char *fullpath, *freepath; 2773 int error; 2774 2775 kif->kf_un.kf_file.kf_file_type = vntype_to_kinfo(vp->v_type); 2776 freepath = NULL; 2777 fullpath = "-"; 2778 error = vn_fullpath(vp, &fullpath, &freepath); 2779 if (error == 0) { 2780 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2781 } 2782 if (freepath != NULL) 2783 free(freepath, M_TEMP); 2784 2785 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2786 vn_fill_junk(kif); 2787 ); 2788 2789 /* 2790 * Retrieve vnode attributes. 2791 */ 2792 va.va_fsid = VNOVAL; 2793 va.va_rdev = NODEV; 2794 vn_lock(vp, LK_SHARED | LK_RETRY); 2795 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2796 VOP_UNLOCK(vp); 2797 if (error != 0) 2798 return (error); 2799 if (va.va_fsid != VNOVAL) 2800 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2801 else 2802 kif->kf_un.kf_file.kf_file_fsid = 2803 vp->v_mount->mnt_stat.f_fsid.val[0]; 2804 kif->kf_un.kf_file.kf_file_fsid_freebsd11 = 2805 kif->kf_un.kf_file.kf_file_fsid; /* truncate */ 2806 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2807 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2808 kif->kf_un.kf_file.kf_file_size = va.va_size; 2809 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2810 kif->kf_un.kf_file.kf_file_rdev_freebsd11 = 2811 kif->kf_un.kf_file.kf_file_rdev; /* truncate */ 2812 kif->kf_un.kf_file.kf_file_nlink = va.va_nlink; 2813 return (0); 2814 } 2815 2816 int 2817 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2818 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2819 struct thread *td) 2820 { 2821 #ifdef HWPMC_HOOKS 2822 struct pmckern_map_in pkm; 2823 #endif 2824 struct mount *mp; 2825 struct vnode *vp; 2826 vm_object_t object; 2827 vm_prot_t maxprot; 2828 boolean_t writecounted; 2829 int error; 2830 2831 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2832 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2833 /* 2834 * POSIX shared-memory objects are defined to have 2835 * kernel persistence, and are not defined to support 2836 * read(2)/write(2) -- or even open(2). Thus, we can 2837 * use MAP_ASYNC to trade on-disk coherence for speed. 2838 * The shm_open(3) library routine turns on the FPOSIXSHM 2839 * flag to request this behavior. 2840 */ 2841 if ((fp->f_flag & FPOSIXSHM) != 0) 2842 flags |= MAP_NOSYNC; 2843 #endif 2844 vp = fp->f_vnode; 2845 2846 /* 2847 * Ensure that file and memory protections are 2848 * compatible. Note that we only worry about 2849 * writability if mapping is shared; in this case, 2850 * current and max prot are dictated by the open file. 2851 * XXX use the vnode instead? Problem is: what 2852 * credentials do we use for determination? What if 2853 * proc does a setuid? 2854 */ 2855 mp = vp->v_mount; 2856 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) { 2857 maxprot = VM_PROT_NONE; 2858 if ((prot & VM_PROT_EXECUTE) != 0) 2859 return (EACCES); 2860 } else 2861 maxprot = VM_PROT_EXECUTE; 2862 if ((fp->f_flag & FREAD) != 0) 2863 maxprot |= VM_PROT_READ; 2864 else if ((prot & VM_PROT_READ) != 0) 2865 return (EACCES); 2866 2867 /* 2868 * If we are sharing potential changes via MAP_SHARED and we 2869 * are trying to get write permission although we opened it 2870 * without asking for it, bail out. 2871 */ 2872 if ((flags & MAP_SHARED) != 0) { 2873 if ((fp->f_flag & FWRITE) != 0) 2874 maxprot |= VM_PROT_WRITE; 2875 else if ((prot & VM_PROT_WRITE) != 0) 2876 return (EACCES); 2877 } else { 2878 maxprot |= VM_PROT_WRITE; 2879 cap_maxprot |= VM_PROT_WRITE; 2880 } 2881 maxprot &= cap_maxprot; 2882 2883 /* 2884 * For regular files and shared memory, POSIX requires that 2885 * the value of foff be a legitimate offset within the data 2886 * object. In particular, negative offsets are invalid. 2887 * Blocking negative offsets and overflows here avoids 2888 * possible wraparound or user-level access into reserved 2889 * ranges of the data object later. In contrast, POSIX does 2890 * not dictate how offsets are used by device drivers, so in 2891 * the case of a device mapping a negative offset is passed 2892 * on. 2893 */ 2894 if ( 2895 #ifdef _LP64 2896 size > OFF_MAX || 2897 #endif 2898 foff > OFF_MAX - size) 2899 return (EINVAL); 2900 2901 writecounted = FALSE; 2902 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2903 &foff, &object, &writecounted); 2904 if (error != 0) 2905 return (error); 2906 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2907 foff, writecounted, td); 2908 if (error != 0) { 2909 /* 2910 * If this mapping was accounted for in the vnode's 2911 * writecount, then undo that now. 2912 */ 2913 if (writecounted) 2914 vm_pager_release_writecount(object, 0, size); 2915 vm_object_deallocate(object); 2916 } 2917 #ifdef HWPMC_HOOKS 2918 /* Inform hwpmc(4) if an executable is being mapped. */ 2919 if (PMC_HOOK_INSTALLED(PMC_FN_MMAP)) { 2920 if ((prot & VM_PROT_EXECUTE) != 0 && error == 0) { 2921 pkm.pm_file = vp; 2922 pkm.pm_address = (uintptr_t) *addr; 2923 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_MMAP, (void *) &pkm); 2924 } 2925 } 2926 #endif 2927 return (error); 2928 } 2929 2930 void 2931 vn_fsid(struct vnode *vp, struct vattr *va) 2932 { 2933 fsid_t *f; 2934 2935 f = &vp->v_mount->mnt_stat.f_fsid; 2936 va->va_fsid = (uint32_t)f->val[1]; 2937 va->va_fsid <<= sizeof(f->val[1]) * NBBY; 2938 va->va_fsid += (uint32_t)f->val[0]; 2939 } 2940 2941 int 2942 vn_fsync_buf(struct vnode *vp, int waitfor) 2943 { 2944 struct buf *bp, *nbp; 2945 struct bufobj *bo; 2946 struct mount *mp; 2947 int error, maxretry; 2948 2949 error = 0; 2950 maxretry = 10000; /* large, arbitrarily chosen */ 2951 mp = NULL; 2952 if (vp->v_type == VCHR) { 2953 VI_LOCK(vp); 2954 mp = vp->v_rdev->si_mountpt; 2955 VI_UNLOCK(vp); 2956 } 2957 bo = &vp->v_bufobj; 2958 BO_LOCK(bo); 2959 loop1: 2960 /* 2961 * MARK/SCAN initialization to avoid infinite loops. 2962 */ 2963 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) { 2964 bp->b_vflags &= ~BV_SCANNED; 2965 bp->b_error = 0; 2966 } 2967 2968 /* 2969 * Flush all dirty buffers associated with a vnode. 2970 */ 2971 loop2: 2972 TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) { 2973 if ((bp->b_vflags & BV_SCANNED) != 0) 2974 continue; 2975 bp->b_vflags |= BV_SCANNED; 2976 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL)) { 2977 if (waitfor != MNT_WAIT) 2978 continue; 2979 if (BUF_LOCK(bp, 2980 LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL, 2981 BO_LOCKPTR(bo)) != 0) { 2982 BO_LOCK(bo); 2983 goto loop1; 2984 } 2985 BO_LOCK(bo); 2986 } 2987 BO_UNLOCK(bo); 2988 KASSERT(bp->b_bufobj == bo, 2989 ("bp %p wrong b_bufobj %p should be %p", 2990 bp, bp->b_bufobj, bo)); 2991 if ((bp->b_flags & B_DELWRI) == 0) 2992 panic("fsync: not dirty"); 2993 if ((vp->v_object != NULL) && (bp->b_flags & B_CLUSTEROK)) { 2994 vfs_bio_awrite(bp); 2995 } else { 2996 bremfree(bp); 2997 bawrite(bp); 2998 } 2999 if (maxretry < 1000) 3000 pause("dirty", hz < 1000 ? 1 : hz / 1000); 3001 BO_LOCK(bo); 3002 goto loop2; 3003 } 3004 3005 /* 3006 * If synchronous the caller expects us to completely resolve all 3007 * dirty buffers in the system. Wait for in-progress I/O to 3008 * complete (which could include background bitmap writes), then 3009 * retry if dirty blocks still exist. 3010 */ 3011 if (waitfor == MNT_WAIT) { 3012 bufobj_wwait(bo, 0, 0); 3013 if (bo->bo_dirty.bv_cnt > 0) { 3014 /* 3015 * If we are unable to write any of these buffers 3016 * then we fail now rather than trying endlessly 3017 * to write them out. 3018 */ 3019 TAILQ_FOREACH(bp, &bo->bo_dirty.bv_hd, b_bobufs) 3020 if ((error = bp->b_error) != 0) 3021 break; 3022 if ((mp != NULL && mp->mnt_secondary_writes > 0) || 3023 (error == 0 && --maxretry >= 0)) 3024 goto loop1; 3025 if (error == 0) 3026 error = EAGAIN; 3027 } 3028 } 3029 BO_UNLOCK(bo); 3030 if (error != 0) 3031 vn_printf(vp, "fsync: giving up on dirty (error = %d) ", error); 3032 3033 return (error); 3034 } 3035 3036 /* 3037 * Copies a byte range from invp to outvp. Calls VOP_COPY_FILE_RANGE() 3038 * or vn_generic_copy_file_range() after rangelocking the byte ranges, 3039 * to do the actual copy. 3040 * vn_generic_copy_file_range() is factored out, so it can be called 3041 * from a VOP_COPY_FILE_RANGE() call as well, but handles vnodes from 3042 * different file systems. 3043 */ 3044 int 3045 vn_copy_file_range(struct vnode *invp, off_t *inoffp, struct vnode *outvp, 3046 off_t *outoffp, size_t *lenp, unsigned int flags, struct ucred *incred, 3047 struct ucred *outcred, struct thread *fsize_td) 3048 { 3049 int error; 3050 size_t len; 3051 uint64_t uval; 3052 3053 len = *lenp; 3054 *lenp = 0; /* For error returns. */ 3055 error = 0; 3056 3057 /* Do some sanity checks on the arguments. */ 3058 if (invp->v_type == VDIR || outvp->v_type == VDIR) 3059 error = EISDIR; 3060 else if (*inoffp < 0 || *outoffp < 0 || 3061 invp->v_type != VREG || outvp->v_type != VREG) 3062 error = EINVAL; 3063 if (error != 0) 3064 goto out; 3065 3066 /* Ensure offset + len does not wrap around. */ 3067 uval = *inoffp; 3068 uval += len; 3069 if (uval > INT64_MAX) 3070 len = INT64_MAX - *inoffp; 3071 uval = *outoffp; 3072 uval += len; 3073 if (uval > INT64_MAX) 3074 len = INT64_MAX - *outoffp; 3075 if (len == 0) 3076 goto out; 3077 3078 /* 3079 * If the two vnodes are for the same file system type, call 3080 * VOP_COPY_FILE_RANGE(), otherwise call vn_generic_copy_file_range() 3081 * which can handle copies across multiple file system types. 3082 */ 3083 *lenp = len; 3084 if (invp->v_mount == outvp->v_mount || 3085 strcmp(invp->v_mount->mnt_vfc->vfc_name, 3086 outvp->v_mount->mnt_vfc->vfc_name) == 0) 3087 error = VOP_COPY_FILE_RANGE(invp, inoffp, outvp, outoffp, 3088 lenp, flags, incred, outcred, fsize_td); 3089 else 3090 error = vn_generic_copy_file_range(invp, inoffp, outvp, 3091 outoffp, lenp, flags, incred, outcred, fsize_td); 3092 out: 3093 return (error); 3094 } 3095 3096 /* 3097 * Test len bytes of data starting at dat for all bytes == 0. 3098 * Return true if all bytes are zero, false otherwise. 3099 * Expects dat to be well aligned. 3100 */ 3101 static bool 3102 mem_iszero(void *dat, int len) 3103 { 3104 int i; 3105 const u_int *p; 3106 const char *cp; 3107 3108 for (p = dat; len > 0; len -= sizeof(*p), p++) { 3109 if (len >= sizeof(*p)) { 3110 if (*p != 0) 3111 return (false); 3112 } else { 3113 cp = (const char *)p; 3114 for (i = 0; i < len; i++, cp++) 3115 if (*cp != '\0') 3116 return (false); 3117 } 3118 } 3119 return (true); 3120 } 3121 3122 /* 3123 * Look for a hole in the output file and, if found, adjust *outoffp 3124 * and *xferp to skip past the hole. 3125 * *xferp is the entire hole length to be written and xfer2 is how many bytes 3126 * to be written as 0's upon return. 3127 */ 3128 static off_t 3129 vn_skip_hole(struct vnode *outvp, off_t xfer2, off_t *outoffp, off_t *xferp, 3130 off_t *dataoffp, off_t *holeoffp, struct ucred *cred) 3131 { 3132 int error; 3133 off_t delta; 3134 3135 if (*holeoffp == 0 || *holeoffp <= *outoffp) { 3136 *dataoffp = *outoffp; 3137 error = VOP_IOCTL(outvp, FIOSEEKDATA, dataoffp, 0, cred, 3138 curthread); 3139 if (error == 0) { 3140 *holeoffp = *dataoffp; 3141 error = VOP_IOCTL(outvp, FIOSEEKHOLE, holeoffp, 0, cred, 3142 curthread); 3143 } 3144 if (error != 0 || *holeoffp == *dataoffp) { 3145 /* 3146 * Since outvp is unlocked, it may be possible for 3147 * another thread to do a truncate(), lseek(), write() 3148 * creating a hole at startoff between the above 3149 * VOP_IOCTL() calls, if the other thread does not do 3150 * rangelocking. 3151 * If that happens, *holeoffp == *dataoffp and finding 3152 * the hole has failed, so disable vn_skip_hole(). 3153 */ 3154 *holeoffp = -1; /* Disable use of vn_skip_hole(). */ 3155 return (xfer2); 3156 } 3157 KASSERT(*dataoffp >= *outoffp, 3158 ("vn_skip_hole: dataoff=%jd < outoff=%jd", 3159 (intmax_t)*dataoffp, (intmax_t)*outoffp)); 3160 KASSERT(*holeoffp > *dataoffp, 3161 ("vn_skip_hole: holeoff=%jd <= dataoff=%jd", 3162 (intmax_t)*holeoffp, (intmax_t)*dataoffp)); 3163 } 3164 3165 /* 3166 * If there is a hole before the data starts, advance *outoffp and 3167 * *xferp past the hole. 3168 */ 3169 if (*dataoffp > *outoffp) { 3170 delta = *dataoffp - *outoffp; 3171 if (delta >= *xferp) { 3172 /* Entire *xferp is a hole. */ 3173 *outoffp += *xferp; 3174 *xferp = 0; 3175 return (0); 3176 } 3177 *xferp -= delta; 3178 *outoffp += delta; 3179 xfer2 = MIN(xfer2, *xferp); 3180 } 3181 3182 /* 3183 * If a hole starts before the end of this xfer2, reduce this xfer2 so 3184 * that the write ends at the start of the hole. 3185 * *holeoffp should always be greater than *outoffp, but for the 3186 * non-INVARIANTS case, check this to make sure xfer2 remains a sane 3187 * value. 3188 */ 3189 if (*holeoffp > *outoffp && *holeoffp < *outoffp + xfer2) 3190 xfer2 = *holeoffp - *outoffp; 3191 return (xfer2); 3192 } 3193 3194 /* 3195 * Write an xfer sized chunk to outvp in blksize blocks from dat. 3196 * dat is a maximum of blksize in length and can be written repeatedly in 3197 * the chunk. 3198 * If growfile == true, just grow the file via vn_truncate_locked() instead 3199 * of doing actual writes. 3200 * If checkhole == true, a hole is being punched, so skip over any hole 3201 * already in the output file. 3202 */ 3203 static int 3204 vn_write_outvp(struct vnode *outvp, char *dat, off_t outoff, off_t xfer, 3205 u_long blksize, bool growfile, bool checkhole, struct ucred *cred) 3206 { 3207 struct mount *mp; 3208 off_t dataoff, holeoff, xfer2; 3209 int error; 3210 3211 /* 3212 * Loop around doing writes of blksize until write has been completed. 3213 * Lock/unlock on each loop iteration so that a bwillwrite() can be 3214 * done for each iteration, since the xfer argument can be very 3215 * large if there is a large hole to punch in the output file. 3216 */ 3217 error = 0; 3218 holeoff = 0; 3219 do { 3220 xfer2 = MIN(xfer, blksize); 3221 if (checkhole) { 3222 /* 3223 * Punching a hole. Skip writing if there is 3224 * already a hole in the output file. 3225 */ 3226 xfer2 = vn_skip_hole(outvp, xfer2, &outoff, &xfer, 3227 &dataoff, &holeoff, cred); 3228 if (xfer == 0) 3229 break; 3230 if (holeoff < 0) 3231 checkhole = false; 3232 KASSERT(xfer2 > 0, ("vn_write_outvp: xfer2=%jd", 3233 (intmax_t)xfer2)); 3234 } 3235 bwillwrite(); 3236 mp = NULL; 3237 error = vn_start_write(outvp, &mp, V_WAIT); 3238 if (error != 0) 3239 break; 3240 if (growfile) { 3241 error = vn_lock(outvp, LK_EXCLUSIVE); 3242 if (error == 0) { 3243 error = vn_truncate_locked(outvp, outoff + xfer, 3244 false, cred); 3245 VOP_UNLOCK(outvp); 3246 } 3247 } else { 3248 error = vn_lock(outvp, vn_lktype_write(mp, outvp)); 3249 if (error == 0) { 3250 error = vn_rdwr(UIO_WRITE, outvp, dat, xfer2, 3251 outoff, UIO_SYSSPACE, IO_NODELOCKED, 3252 curthread->td_ucred, cred, NULL, curthread); 3253 outoff += xfer2; 3254 xfer -= xfer2; 3255 VOP_UNLOCK(outvp); 3256 } 3257 } 3258 if (mp != NULL) 3259 vn_finished_write(mp); 3260 } while (!growfile && xfer > 0 && error == 0); 3261 return (error); 3262 } 3263 3264 /* 3265 * Copy a byte range of one file to another. This function can handle the 3266 * case where invp and outvp are on different file systems. 3267 * It can also be called by a VOP_COPY_FILE_RANGE() to do the work, if there 3268 * is no better file system specific way to do it. 3269 */ 3270 int 3271 vn_generic_copy_file_range(struct vnode *invp, off_t *inoffp, 3272 struct vnode *outvp, off_t *outoffp, size_t *lenp, unsigned int flags, 3273 struct ucred *incred, struct ucred *outcred, struct thread *fsize_td) 3274 { 3275 struct mount *mp; 3276 off_t startoff, endoff, xfer, xfer2; 3277 u_long blksize; 3278 int error, interrupted; 3279 bool cantseek, readzeros, eof, lastblock, holetoeof; 3280 ssize_t aresid, r = 0; 3281 size_t copylen, len, savlen; 3282 off_t insize, outsize; 3283 char *dat; 3284 long holein, holeout; 3285 struct timespec curts, endts; 3286 3287 holein = holeout = 0; 3288 savlen = len = *lenp; 3289 error = 0; 3290 interrupted = 0; 3291 dat = NULL; 3292 3293 error = vn_lock(invp, LK_SHARED); 3294 if (error != 0) 3295 goto out; 3296 if (VOP_PATHCONF(invp, _PC_MIN_HOLE_SIZE, &holein) != 0) 3297 holein = 0; 3298 if (holein > 0) 3299 error = vn_getsize_locked(invp, &insize, incred); 3300 VOP_UNLOCK(invp); 3301 if (error != 0) 3302 goto out; 3303 3304 mp = NULL; 3305 error = vn_start_write(outvp, &mp, V_WAIT); 3306 if (error == 0) 3307 error = vn_lock(outvp, LK_EXCLUSIVE); 3308 if (error == 0) { 3309 /* 3310 * If fsize_td != NULL, do a vn_rlimit_fsizex() call, 3311 * now that outvp is locked. 3312 */ 3313 if (fsize_td != NULL) { 3314 struct uio io; 3315 3316 io.uio_offset = *outoffp; 3317 io.uio_resid = len; 3318 error = vn_rlimit_fsizex(outvp, &io, 0, &r, fsize_td); 3319 len = savlen = io.uio_resid; 3320 /* 3321 * No need to call vn_rlimit_fsizex_res before return, 3322 * since the uio is local. 3323 */ 3324 } 3325 if (VOP_PATHCONF(outvp, _PC_MIN_HOLE_SIZE, &holeout) != 0) 3326 holeout = 0; 3327 /* 3328 * Holes that are past EOF do not need to be written as a block 3329 * of zero bytes. So, truncate the output file as far as 3330 * possible and then use size to decide if writing 0 3331 * bytes is necessary in the loop below. 3332 */ 3333 if (error == 0) 3334 error = vn_getsize_locked(outvp, &outsize, outcred); 3335 if (error == 0 && outsize > *outoffp && outsize <= *outoffp + len) { 3336 #ifdef MAC 3337 error = mac_vnode_check_write(curthread->td_ucred, 3338 outcred, outvp); 3339 if (error == 0) 3340 #endif 3341 error = vn_truncate_locked(outvp, *outoffp, 3342 false, outcred); 3343 if (error == 0) 3344 outsize = *outoffp; 3345 } 3346 VOP_UNLOCK(outvp); 3347 } 3348 if (mp != NULL) 3349 vn_finished_write(mp); 3350 if (error != 0) 3351 goto out; 3352 3353 if (holein == 0 && holeout > 0) { 3354 /* 3355 * For this special case, the input data will be scanned 3356 * for blocks of all 0 bytes. For these blocks, the 3357 * write can be skipped for the output file to create 3358 * an unallocated region. 3359 * Therefore, use the appropriate size for the output file. 3360 */ 3361 blksize = holeout; 3362 if (blksize <= 512) { 3363 /* 3364 * Use f_iosize, since ZFS reports a _PC_MIN_HOLE_SIZE 3365 * of 512, although it actually only creates 3366 * unallocated regions for blocks >= f_iosize. 3367 */ 3368 blksize = outvp->v_mount->mnt_stat.f_iosize; 3369 } 3370 } else { 3371 /* 3372 * Use the larger of the two f_iosize values. If they are 3373 * not the same size, one will normally be an exact multiple of 3374 * the other, since they are both likely to be a power of 2. 3375 */ 3376 blksize = MAX(invp->v_mount->mnt_stat.f_iosize, 3377 outvp->v_mount->mnt_stat.f_iosize); 3378 } 3379 3380 /* Clip to sane limits. */ 3381 if (blksize < 4096) 3382 blksize = 4096; 3383 else if (blksize > maxphys) 3384 blksize = maxphys; 3385 dat = malloc(blksize, M_TEMP, M_WAITOK); 3386 3387 /* 3388 * If VOP_IOCTL(FIOSEEKHOLE) works for invp, use it and FIOSEEKDATA 3389 * to find holes. Otherwise, just scan the read block for all 0s 3390 * in the inner loop where the data copying is done. 3391 * Note that some file systems such as NFSv3, NFSv4.0 and NFSv4.1 may 3392 * support holes on the server, but do not support FIOSEEKHOLE. 3393 * The kernel flag COPY_FILE_RANGE_TIMEO1SEC is used to indicate 3394 * that this function should return after 1second with a partial 3395 * completion. 3396 */ 3397 if ((flags & COPY_FILE_RANGE_TIMEO1SEC) != 0) { 3398 getnanouptime(&endts); 3399 endts.tv_sec++; 3400 } else 3401 timespecclear(&endts); 3402 holetoeof = eof = false; 3403 while (len > 0 && error == 0 && !eof && interrupted == 0) { 3404 endoff = 0; /* To shut up compilers. */ 3405 cantseek = true; 3406 startoff = *inoffp; 3407 copylen = len; 3408 3409 /* 3410 * Find the next data area. If there is just a hole to EOF, 3411 * FIOSEEKDATA should fail with ENXIO. 3412 * (I do not know if any file system will report a hole to 3413 * EOF via FIOSEEKHOLE, but I am pretty sure FIOSEEKDATA 3414 * will fail for those file systems.) 3415 * 3416 * For input files that don't support FIOSEEKDATA/FIOSEEKHOLE, 3417 * the code just falls through to the inner copy loop. 3418 */ 3419 error = EINVAL; 3420 if (holein > 0) { 3421 error = VOP_IOCTL(invp, FIOSEEKDATA, &startoff, 0, 3422 incred, curthread); 3423 if (error == ENXIO) { 3424 startoff = endoff = insize; 3425 eof = holetoeof = true; 3426 error = 0; 3427 } 3428 } 3429 if (error == 0 && !holetoeof) { 3430 endoff = startoff; 3431 error = VOP_IOCTL(invp, FIOSEEKHOLE, &endoff, 0, 3432 incred, curthread); 3433 /* 3434 * Since invp is unlocked, it may be possible for 3435 * another thread to do a truncate(), lseek(), write() 3436 * creating a hole at startoff between the above 3437 * VOP_IOCTL() calls, if the other thread does not do 3438 * rangelocking. 3439 * If that happens, startoff == endoff and finding 3440 * the hole has failed, so set an error. 3441 */ 3442 if (error == 0 && startoff == endoff) 3443 error = EINVAL; /* Any error. Reset to 0. */ 3444 } 3445 if (error == 0) { 3446 if (startoff > *inoffp) { 3447 /* Found hole before data block. */ 3448 xfer = MIN(startoff - *inoffp, len); 3449 if (*outoffp < outsize) { 3450 /* Must write 0s to punch hole. */ 3451 xfer2 = MIN(outsize - *outoffp, 3452 xfer); 3453 memset(dat, 0, MIN(xfer2, blksize)); 3454 error = vn_write_outvp(outvp, dat, 3455 *outoffp, xfer2, blksize, false, 3456 holeout > 0, outcred); 3457 } 3458 3459 if (error == 0 && *outoffp + xfer > 3460 outsize && (xfer == len || holetoeof)) { 3461 /* Grow output file (hole at end). */ 3462 error = vn_write_outvp(outvp, dat, 3463 *outoffp, xfer, blksize, true, 3464 false, outcred); 3465 } 3466 if (error == 0) { 3467 *inoffp += xfer; 3468 *outoffp += xfer; 3469 len -= xfer; 3470 if (len < savlen) { 3471 interrupted = sig_intr(); 3472 if (timespecisset(&endts) && 3473 interrupted == 0) { 3474 getnanouptime(&curts); 3475 if (timespeccmp(&curts, 3476 &endts, >=)) 3477 interrupted = 3478 EINTR; 3479 } 3480 } 3481 } 3482 } 3483 copylen = MIN(len, endoff - startoff); 3484 cantseek = false; 3485 } else { 3486 cantseek = true; 3487 startoff = *inoffp; 3488 copylen = len; 3489 error = 0; 3490 } 3491 3492 xfer = blksize; 3493 if (cantseek) { 3494 /* 3495 * Set first xfer to end at a block boundary, so that 3496 * holes are more likely detected in the loop below via 3497 * the for all bytes 0 method. 3498 */ 3499 xfer -= (*inoffp % blksize); 3500 } 3501 /* Loop copying the data block. */ 3502 while (copylen > 0 && error == 0 && !eof && interrupted == 0) { 3503 if (copylen < xfer) 3504 xfer = copylen; 3505 error = vn_lock(invp, LK_SHARED); 3506 if (error != 0) 3507 goto out; 3508 error = vn_rdwr(UIO_READ, invp, dat, xfer, 3509 startoff, UIO_SYSSPACE, IO_NODELOCKED, 3510 curthread->td_ucred, incred, &aresid, 3511 curthread); 3512 VOP_UNLOCK(invp); 3513 lastblock = false; 3514 if (error == 0 && aresid > 0) { 3515 /* Stop the copy at EOF on the input file. */ 3516 xfer -= aresid; 3517 eof = true; 3518 lastblock = true; 3519 } 3520 if (error == 0) { 3521 /* 3522 * Skip the write for holes past the initial EOF 3523 * of the output file, unless this is the last 3524 * write of the output file at EOF. 3525 */ 3526 readzeros = cantseek ? mem_iszero(dat, xfer) : 3527 false; 3528 if (xfer == len) 3529 lastblock = true; 3530 if (!cantseek || *outoffp < outsize || 3531 lastblock || !readzeros) 3532 error = vn_write_outvp(outvp, dat, 3533 *outoffp, xfer, blksize, 3534 readzeros && lastblock && 3535 *outoffp >= outsize, false, 3536 outcred); 3537 if (error == 0) { 3538 *inoffp += xfer; 3539 startoff += xfer; 3540 *outoffp += xfer; 3541 copylen -= xfer; 3542 len -= xfer; 3543 if (len < savlen) { 3544 interrupted = sig_intr(); 3545 if (timespecisset(&endts) && 3546 interrupted == 0) { 3547 getnanouptime(&curts); 3548 if (timespeccmp(&curts, 3549 &endts, >=)) 3550 interrupted = 3551 EINTR; 3552 } 3553 } 3554 } 3555 } 3556 xfer = blksize; 3557 } 3558 } 3559 out: 3560 *lenp = savlen - len; 3561 free(dat, M_TEMP); 3562 return (error); 3563 } 3564 3565 static int 3566 vn_fallocate(struct file *fp, off_t offset, off_t len, struct thread *td) 3567 { 3568 struct mount *mp; 3569 struct vnode *vp; 3570 off_t olen, ooffset; 3571 int error; 3572 #ifdef AUDIT 3573 int audited_vnode1 = 0; 3574 #endif 3575 3576 vp = fp->f_vnode; 3577 if (vp->v_type != VREG) 3578 return (ENODEV); 3579 3580 /* Allocating blocks may take a long time, so iterate. */ 3581 for (;;) { 3582 olen = len; 3583 ooffset = offset; 3584 3585 bwillwrite(); 3586 mp = NULL; 3587 error = vn_start_write(vp, &mp, V_WAIT | V_PCATCH); 3588 if (error != 0) 3589 break; 3590 error = vn_lock(vp, LK_EXCLUSIVE); 3591 if (error != 0) { 3592 vn_finished_write(mp); 3593 break; 3594 } 3595 #ifdef AUDIT 3596 if (!audited_vnode1) { 3597 AUDIT_ARG_VNODE1(vp); 3598 audited_vnode1 = 1; 3599 } 3600 #endif 3601 #ifdef MAC 3602 error = mac_vnode_check_write(td->td_ucred, fp->f_cred, vp); 3603 if (error == 0) 3604 #endif 3605 error = VOP_ALLOCATE(vp, &offset, &len, 0, 3606 td->td_ucred); 3607 VOP_UNLOCK(vp); 3608 vn_finished_write(mp); 3609 3610 if (olen + ooffset != offset + len) { 3611 panic("offset + len changed from %jx/%jx to %jx/%jx", 3612 ooffset, olen, offset, len); 3613 } 3614 if (error != 0 || len == 0) 3615 break; 3616 KASSERT(olen > len, ("Iteration did not make progress?")); 3617 maybe_yield(); 3618 } 3619 3620 return (error); 3621 } 3622 3623 static int 3624 vn_deallocate_impl(struct vnode *vp, off_t *offset, off_t *length, int flags, 3625 int ioflag, struct ucred *cred, struct ucred *active_cred, 3626 struct ucred *file_cred) 3627 { 3628 struct mount *mp; 3629 void *rl_cookie; 3630 off_t off, len; 3631 int error; 3632 #ifdef AUDIT 3633 bool audited_vnode1 = false; 3634 #endif 3635 3636 rl_cookie = NULL; 3637 error = 0; 3638 mp = NULL; 3639 off = *offset; 3640 len = *length; 3641 3642 if ((ioflag & (IO_NODELOCKED | IO_RANGELOCKED)) == 0) 3643 rl_cookie = vn_rangelock_wlock(vp, off, off + len); 3644 while (len > 0 && error == 0) { 3645 /* 3646 * Try to deallocate the longest range in one pass. 3647 * In case a pass takes too long to be executed, it returns 3648 * partial result. The residue will be proceeded in the next 3649 * pass. 3650 */ 3651 3652 if ((ioflag & IO_NODELOCKED) == 0) { 3653 bwillwrite(); 3654 if ((error = vn_start_write(vp, &mp, 3655 V_WAIT | V_PCATCH)) != 0) 3656 goto out; 3657 vn_lock(vp, vn_lktype_write(mp, vp) | LK_RETRY); 3658 } 3659 #ifdef AUDIT 3660 if (!audited_vnode1) { 3661 AUDIT_ARG_VNODE1(vp); 3662 audited_vnode1 = true; 3663 } 3664 #endif 3665 3666 #ifdef MAC 3667 if ((ioflag & IO_NOMACCHECK) == 0) 3668 error = mac_vnode_check_write(active_cred, file_cred, 3669 vp); 3670 #endif 3671 if (error == 0) 3672 error = VOP_DEALLOCATE(vp, &off, &len, flags, ioflag, 3673 cred); 3674 3675 if ((ioflag & IO_NODELOCKED) == 0) { 3676 VOP_UNLOCK(vp); 3677 if (mp != NULL) { 3678 vn_finished_write(mp); 3679 mp = NULL; 3680 } 3681 } 3682 if (error == 0 && len != 0) 3683 maybe_yield(); 3684 } 3685 out: 3686 if (rl_cookie != NULL) 3687 vn_rangelock_unlock(vp, rl_cookie); 3688 *offset = off; 3689 *length = len; 3690 return (error); 3691 } 3692 3693 /* 3694 * This function is supposed to be used in the situations where the deallocation 3695 * is not triggered by a user request. 3696 */ 3697 int 3698 vn_deallocate(struct vnode *vp, off_t *offset, off_t *length, int flags, 3699 int ioflag, struct ucred *active_cred, struct ucred *file_cred) 3700 { 3701 struct ucred *cred; 3702 3703 if (*offset < 0 || *length <= 0 || *length > OFF_MAX - *offset || 3704 flags != 0) 3705 return (EINVAL); 3706 if (vp->v_type != VREG) 3707 return (ENODEV); 3708 3709 cred = file_cred != NOCRED ? file_cred : active_cred; 3710 return (vn_deallocate_impl(vp, offset, length, flags, ioflag, cred, 3711 active_cred, file_cred)); 3712 } 3713 3714 static int 3715 vn_fspacectl(struct file *fp, int cmd, off_t *offset, off_t *length, int flags, 3716 struct ucred *active_cred, struct thread *td) 3717 { 3718 int error; 3719 struct vnode *vp; 3720 int ioflag; 3721 3722 KASSERT(cmd == SPACECTL_DEALLOC, ("vn_fspacectl: Invalid cmd")); 3723 KASSERT((flags & ~SPACECTL_F_SUPPORTED) == 0, 3724 ("vn_fspacectl: non-zero flags")); 3725 KASSERT(*offset >= 0 && *length > 0 && *length <= OFF_MAX - *offset, 3726 ("vn_fspacectl: offset/length overflow or underflow")); 3727 vp = fp->f_vnode; 3728 3729 if (vp->v_type != VREG) 3730 return (ENODEV); 3731 3732 ioflag = get_write_ioflag(fp); 3733 3734 switch (cmd) { 3735 case SPACECTL_DEALLOC: 3736 error = vn_deallocate_impl(vp, offset, length, flags, ioflag, 3737 active_cred, active_cred, fp->f_cred); 3738 break; 3739 default: 3740 panic("vn_fspacectl: unknown cmd %d", cmd); 3741 } 3742 3743 return (error); 3744 } 3745 3746 /* 3747 * Keep this assert as long as sizeof(struct dirent) is used as the maximum 3748 * entry size. 3749 */ 3750 _Static_assert(_GENERIC_MAXDIRSIZ == sizeof(struct dirent), 3751 "'struct dirent' size must be a multiple of its alignment " 3752 "(see _GENERIC_DIRLEN())"); 3753 3754 /* 3755 * Returns successive directory entries through some caller's provided buffer. 3756 * 3757 * This function automatically refills the provided buffer with calls to 3758 * VOP_READDIR() (after MAC permission checks). 3759 * 3760 * 'td' is used for credentials and passed to uiomove(). 'dirbuf' is the 3761 * caller's buffer to fill and 'dirbuflen' its allocated size. 'dirbuf' must 3762 * be properly aligned to access 'struct dirent' structures and 'dirbuflen' 3763 * must be greater than GENERIC_MAXDIRSIZ to avoid VOP_READDIR() returning 3764 * EINVAL (the latter is not a strong guarantee (yet); but EINVAL will always 3765 * be returned if this requirement is not verified). '*dpp' points to the 3766 * current directory entry in the buffer and '*len' contains the remaining 3767 * valid bytes in 'dirbuf' after 'dpp' (including the pointed entry). 3768 * 3769 * At first call (or when restarting the read), '*len' must have been set to 0, 3770 * '*off' to 0 (or any valid start offset) and '*eofflag' to 0. There are no 3771 * more entries as soon as '*len' is 0 after a call that returned 0. Calling 3772 * again this function after such a condition is considered an error and EINVAL 3773 * will be returned. Other possible error codes are those of VOP_READDIR(), 3774 * EINTEGRITY if the returned entries do not pass coherency tests, or EINVAL 3775 * (bad call). All errors are unrecoverable, i.e., the state ('*len', '*off' 3776 * and '*eofflag') must be re-initialized before a subsequent call. On error 3777 * or at end of directory, '*dpp' is reset to NULL. 3778 * 3779 * '*len', '*off' and '*eofflag' are internal state the caller should not 3780 * tamper with except as explained above. '*off' is the next directory offset 3781 * to read from to refill the buffer. '*eofflag' is set to 0 or 1 by the last 3782 * internal call to VOP_READDIR() that returned without error, indicating 3783 * whether it reached the end of the directory, and to 2 by this function after 3784 * all entries have been read. 3785 */ 3786 int 3787 vn_dir_next_dirent(struct vnode *vp, struct thread *td, 3788 char *dirbuf, size_t dirbuflen, 3789 struct dirent **dpp, size_t *len, off_t *off, int *eofflag) 3790 { 3791 struct dirent *dp = NULL; 3792 int reclen; 3793 int error; 3794 struct uio uio; 3795 struct iovec iov; 3796 3797 ASSERT_VOP_LOCKED(vp, "vnode not locked"); 3798 VNASSERT(vp->v_type == VDIR, vp, ("vnode is not a directory")); 3799 MPASS2((uintptr_t)dirbuf < (uintptr_t)dirbuf + dirbuflen, 3800 "Address space overflow"); 3801 3802 if (__predict_false(dirbuflen < GENERIC_MAXDIRSIZ)) { 3803 /* Don't take any chances in this case */ 3804 error = EINVAL; 3805 goto out; 3806 } 3807 3808 if (*len != 0) { 3809 dp = *dpp; 3810 3811 /* 3812 * The caller continued to call us after an error (we set dp to 3813 * NULL in a previous iteration). Bail out right now. 3814 */ 3815 if (__predict_false(dp == NULL)) 3816 return (EINVAL); 3817 3818 MPASS(*len <= dirbuflen); 3819 MPASS2((uintptr_t)dirbuf <= (uintptr_t)dp && 3820 (uintptr_t)dp + *len <= (uintptr_t)dirbuf + dirbuflen, 3821 "Filled range not inside buffer"); 3822 3823 reclen = dp->d_reclen; 3824 if (reclen >= *len) { 3825 /* End of buffer reached */ 3826 *len = 0; 3827 } else { 3828 dp = (struct dirent *)((char *)dp + reclen); 3829 *len -= reclen; 3830 } 3831 } 3832 3833 if (*len == 0) { 3834 dp = NULL; 3835 3836 /* Have to refill. */ 3837 switch (*eofflag) { 3838 case 0: 3839 break; 3840 3841 case 1: 3842 /* Nothing more to read. */ 3843 *eofflag = 2; /* Remember the caller reached EOF. */ 3844 goto success; 3845 3846 default: 3847 /* The caller didn't test for EOF. */ 3848 error = EINVAL; 3849 goto out; 3850 } 3851 3852 iov.iov_base = dirbuf; 3853 iov.iov_len = dirbuflen; 3854 3855 uio.uio_iov = &iov; 3856 uio.uio_iovcnt = 1; 3857 uio.uio_offset = *off; 3858 uio.uio_resid = dirbuflen; 3859 uio.uio_segflg = UIO_SYSSPACE; 3860 uio.uio_rw = UIO_READ; 3861 uio.uio_td = td; 3862 3863 #ifdef MAC 3864 error = mac_vnode_check_readdir(td->td_ucred, vp); 3865 if (error == 0) 3866 #endif 3867 error = VOP_READDIR(vp, &uio, td->td_ucred, eofflag, 3868 NULL, NULL); 3869 if (error != 0) 3870 goto out; 3871 3872 *len = dirbuflen - uio.uio_resid; 3873 *off = uio.uio_offset; 3874 3875 if (*len == 0) { 3876 /* Sanity check on INVARIANTS. */ 3877 MPASS(*eofflag != 0); 3878 *eofflag = 1; 3879 goto success; 3880 } 3881 3882 /* 3883 * Normalize the flag returned by VOP_READDIR(), since we use 2 3884 * as a sentinel value. 3885 */ 3886 if (*eofflag != 0) 3887 *eofflag = 1; 3888 3889 dp = (struct dirent *)dirbuf; 3890 } 3891 3892 if (__predict_false(*len < GENERIC_MINDIRSIZ || 3893 dp->d_reclen < GENERIC_MINDIRSIZ)) { 3894 error = EINTEGRITY; 3895 dp = NULL; 3896 goto out; 3897 } 3898 3899 success: 3900 error = 0; 3901 out: 3902 *dpp = dp; 3903 return (error); 3904 } 3905 3906 /* 3907 * Checks whether a directory is empty or not. 3908 * 3909 * If the directory is empty, returns 0, and if it is not, ENOTEMPTY. Other 3910 * values are genuine errors preventing the check. 3911 */ 3912 int 3913 vn_dir_check_empty(struct vnode *vp) 3914 { 3915 struct thread *const td = curthread; 3916 char *dirbuf; 3917 size_t dirbuflen, len; 3918 off_t off; 3919 int eofflag, error; 3920 struct dirent *dp; 3921 struct vattr va; 3922 3923 ASSERT_VOP_LOCKED(vp, "vfs_emptydir"); 3924 VNPASS(vp->v_type == VDIR, vp); 3925 3926 error = VOP_GETATTR(vp, &va, td->td_ucred); 3927 if (error != 0) 3928 return (error); 3929 3930 dirbuflen = max(DEV_BSIZE, GENERIC_MAXDIRSIZ); 3931 if (dirbuflen < va.va_blocksize) 3932 dirbuflen = va.va_blocksize; 3933 dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK); 3934 3935 len = 0; 3936 off = 0; 3937 eofflag = 0; 3938 3939 for (;;) { 3940 error = vn_dir_next_dirent(vp, td, dirbuf, dirbuflen, 3941 &dp, &len, &off, &eofflag); 3942 if (error != 0) 3943 goto end; 3944 3945 if (len == 0) { 3946 /* EOF */ 3947 error = 0; 3948 goto end; 3949 } 3950 3951 /* 3952 * Skip whiteouts. Unionfs operates on filesystems only and 3953 * not on hierarchies, so these whiteouts would be shadowed on 3954 * the system hierarchy but not for a union using the 3955 * filesystem of their directories as the upper layer. 3956 * Additionally, unionfs currently transparently exposes 3957 * union-specific metadata of its upper layer, meaning that 3958 * whiteouts can be seen through the union view in empty 3959 * directories. Taking into account these whiteouts would then 3960 * prevent mounting another filesystem on such effectively 3961 * empty directories. 3962 */ 3963 if (dp->d_type == DT_WHT) 3964 continue; 3965 3966 /* 3967 * Any file in the directory which is not '.' or '..' indicates 3968 * the directory is not empty. 3969 */ 3970 switch (dp->d_namlen) { 3971 case 2: 3972 if (dp->d_name[1] != '.') { 3973 /* Can't be '..' (nor '.') */ 3974 error = ENOTEMPTY; 3975 goto end; 3976 } 3977 /* FALLTHROUGH */ 3978 case 1: 3979 if (dp->d_name[0] != '.') { 3980 /* Can't be '..' nor '.' */ 3981 error = ENOTEMPTY; 3982 goto end; 3983 } 3984 break; 3985 3986 default: 3987 error = ENOTEMPTY; 3988 goto end; 3989 } 3990 } 3991 3992 end: 3993 free(dirbuf, M_TEMP); 3994 return (error); 3995 } 3996 3997 3998 static u_long vn_lock_pair_pause_cnt; 3999 SYSCTL_ULONG(_debug, OID_AUTO, vn_lock_pair_pause, CTLFLAG_RD, 4000 &vn_lock_pair_pause_cnt, 0, 4001 "Count of vn_lock_pair deadlocks"); 4002 4003 u_int vn_lock_pair_pause_max; 4004 SYSCTL_UINT(_debug, OID_AUTO, vn_lock_pair_pause_max, CTLFLAG_RW, 4005 &vn_lock_pair_pause_max, 0, 4006 "Max ticks for vn_lock_pair deadlock avoidance sleep"); 4007 4008 static void 4009 vn_lock_pair_pause(const char *wmesg) 4010 { 4011 atomic_add_long(&vn_lock_pair_pause_cnt, 1); 4012 pause(wmesg, prng32_bounded(vn_lock_pair_pause_max)); 4013 } 4014 4015 /* 4016 * Lock pair of vnodes vp1, vp2, avoiding lock order reversal. 4017 * vp1_locked indicates whether vp1 is locked; if not, vp1 must be 4018 * unlocked. Same for vp2 and vp2_locked. One of the vnodes can be 4019 * NULL. 4020 * 4021 * The function returns with both vnodes exclusively or shared locked, 4022 * according to corresponding lkflags, and guarantees that it does not 4023 * create lock order reversal with other threads during its execution. 4024 * Both vnodes could be unlocked temporary (and reclaimed). 4025 * 4026 * If requesting shared locking, locked vnode lock must not be recursed. 4027 * 4028 * Only one of LK_SHARED and LK_EXCLUSIVE must be specified. 4029 * LK_NODDLKTREAT can be optionally passed. 4030 */ 4031 void 4032 vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1, 4033 struct vnode *vp2, bool vp2_locked, int lkflags2) 4034 { 4035 int error; 4036 4037 MPASS(((lkflags1 & LK_SHARED) != 0) ^ ((lkflags1 & LK_EXCLUSIVE) != 0)); 4038 MPASS((lkflags1 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0); 4039 MPASS(((lkflags2 & LK_SHARED) != 0) ^ ((lkflags2 & LK_EXCLUSIVE) != 0)); 4040 MPASS((lkflags2 & ~(LK_SHARED | LK_EXCLUSIVE | LK_NODDLKTREAT)) == 0); 4041 4042 if (vp1 == NULL && vp2 == NULL) 4043 return; 4044 4045 if (vp1 != NULL) { 4046 if ((lkflags1 & LK_SHARED) != 0 && 4047 (vp1->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0) 4048 lkflags1 = (lkflags1 & ~LK_SHARED) | LK_EXCLUSIVE; 4049 if (vp1_locked && VOP_ISLOCKED(vp1) != LK_EXCLUSIVE) { 4050 ASSERT_VOP_LOCKED(vp1, "vp1"); 4051 if ((lkflags1 & LK_EXCLUSIVE) != 0) { 4052 VOP_UNLOCK(vp1); 4053 ASSERT_VOP_UNLOCKED(vp1, 4054 "vp1 shared recursed"); 4055 vp1_locked = false; 4056 } 4057 } else if (!vp1_locked) 4058 ASSERT_VOP_UNLOCKED(vp1, "vp1"); 4059 } else { 4060 vp1_locked = true; 4061 } 4062 4063 if (vp2 != NULL) { 4064 if ((lkflags2 & LK_SHARED) != 0 && 4065 (vp2->v_vnlock->lock_object.lo_flags & LK_NOSHARE) != 0) 4066 lkflags2 = (lkflags2 & ~LK_SHARED) | LK_EXCLUSIVE; 4067 if (vp2_locked && VOP_ISLOCKED(vp2) != LK_EXCLUSIVE) { 4068 ASSERT_VOP_LOCKED(vp2, "vp2"); 4069 if ((lkflags2 & LK_EXCLUSIVE) != 0) { 4070 VOP_UNLOCK(vp2); 4071 ASSERT_VOP_UNLOCKED(vp2, 4072 "vp2 shared recursed"); 4073 vp2_locked = false; 4074 } 4075 } else if (!vp2_locked) 4076 ASSERT_VOP_UNLOCKED(vp2, "vp2"); 4077 } else { 4078 vp2_locked = true; 4079 } 4080 4081 if (!vp1_locked && !vp2_locked) { 4082 vn_lock(vp1, lkflags1 | LK_RETRY); 4083 vp1_locked = true; 4084 } 4085 4086 while (!vp1_locked || !vp2_locked) { 4087 if (vp1_locked && vp2 != NULL) { 4088 if (vp1 != NULL) { 4089 error = VOP_LOCK1(vp2, lkflags2 | LK_NOWAIT, 4090 __FILE__, __LINE__); 4091 if (error == 0) 4092 break; 4093 VOP_UNLOCK(vp1); 4094 vp1_locked = false; 4095 vn_lock_pair_pause("vlp1"); 4096 } 4097 vn_lock(vp2, lkflags2 | LK_RETRY); 4098 vp2_locked = true; 4099 } 4100 if (vp2_locked && vp1 != NULL) { 4101 if (vp2 != NULL) { 4102 error = VOP_LOCK1(vp1, lkflags1 | LK_NOWAIT, 4103 __FILE__, __LINE__); 4104 if (error == 0) 4105 break; 4106 VOP_UNLOCK(vp2); 4107 vp2_locked = false; 4108 vn_lock_pair_pause("vlp2"); 4109 } 4110 vn_lock(vp1, lkflags1 | LK_RETRY); 4111 vp1_locked = true; 4112 } 4113 } 4114 if (vp1 != NULL) { 4115 if (lkflags1 == LK_EXCLUSIVE) 4116 ASSERT_VOP_ELOCKED(vp1, "vp1 ret"); 4117 else 4118 ASSERT_VOP_LOCKED(vp1, "vp1 ret"); 4119 } 4120 if (vp2 != NULL) { 4121 if (lkflags2 == LK_EXCLUSIVE) 4122 ASSERT_VOP_ELOCKED(vp2, "vp2 ret"); 4123 else 4124 ASSERT_VOP_LOCKED(vp2, "vp2 ret"); 4125 } 4126 } 4127 4128 int 4129 vn_lktype_write(struct mount *mp, struct vnode *vp) 4130 { 4131 if (MNT_SHARED_WRITES(mp) || 4132 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) 4133 return (LK_SHARED); 4134 return (LK_EXCLUSIVE); 4135 } 4136