1 /*- 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Copyright (c) 2012 Konstantin Belousov <kib@FreeBSD.org> 11 * Copyright (c) 2013, 2014 The FreeBSD Foundation 12 * 13 * Portions of this software were developed by Konstantin Belousov 14 * under sponsorship from the FreeBSD Foundation. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94 41 */ 42 43 #include <sys/cdefs.h> 44 __FBSDID("$FreeBSD$"); 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/disk.h> 49 #include <sys/fail.h> 50 #include <sys/fcntl.h> 51 #include <sys/file.h> 52 #include <sys/kdb.h> 53 #include <sys/stat.h> 54 #include <sys/priv.h> 55 #include <sys/proc.h> 56 #include <sys/limits.h> 57 #include <sys/lock.h> 58 #include <sys/mman.h> 59 #include <sys/mount.h> 60 #include <sys/mutex.h> 61 #include <sys/namei.h> 62 #include <sys/vnode.h> 63 #include <sys/bio.h> 64 #include <sys/buf.h> 65 #include <sys/filio.h> 66 #include <sys/resourcevar.h> 67 #include <sys/rwlock.h> 68 #include <sys/sx.h> 69 #include <sys/sysctl.h> 70 #include <sys/ttycom.h> 71 #include <sys/conf.h> 72 #include <sys/syslog.h> 73 #include <sys/unistd.h> 74 #include <sys/user.h> 75 76 #include <security/audit/audit.h> 77 #include <security/mac/mac_framework.h> 78 79 #include <vm/vm.h> 80 #include <vm/vm_extern.h> 81 #include <vm/pmap.h> 82 #include <vm/vm_map.h> 83 #include <vm/vm_object.h> 84 #include <vm/vm_page.h> 85 #include <vm/vnode_pager.h> 86 87 static fo_rdwr_t vn_read; 88 static fo_rdwr_t vn_write; 89 static fo_rdwr_t vn_io_fault; 90 static fo_truncate_t vn_truncate; 91 static fo_ioctl_t vn_ioctl; 92 static fo_poll_t vn_poll; 93 static fo_kqfilter_t vn_kqfilter; 94 static fo_stat_t vn_statfile; 95 static fo_close_t vn_closefile; 96 static fo_mmap_t vn_mmap; 97 98 struct fileops vnops = { 99 .fo_read = vn_io_fault, 100 .fo_write = vn_io_fault, 101 .fo_truncate = vn_truncate, 102 .fo_ioctl = vn_ioctl, 103 .fo_poll = vn_poll, 104 .fo_kqfilter = vn_kqfilter, 105 .fo_stat = vn_statfile, 106 .fo_close = vn_closefile, 107 .fo_chmod = vn_chmod, 108 .fo_chown = vn_chown, 109 .fo_sendfile = vn_sendfile, 110 .fo_seek = vn_seek, 111 .fo_fill_kinfo = vn_fill_kinfo, 112 .fo_mmap = vn_mmap, 113 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE 114 }; 115 116 static const int io_hold_cnt = 16; 117 static int vn_io_fault_enable = 1; 118 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RW, 119 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance"); 120 static int vn_io_fault_prefault = 0; 121 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RW, 122 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting"); 123 static u_long vn_io_faults_cnt; 124 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, 125 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); 126 127 /* 128 * Returns true if vn_io_fault mode of handling the i/o request should 129 * be used. 130 */ 131 static bool 132 do_vn_io_fault(struct vnode *vp, struct uio *uio) 133 { 134 struct mount *mp; 135 136 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG && 137 (mp = vp->v_mount) != NULL && 138 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable); 139 } 140 141 /* 142 * Structure used to pass arguments to vn_io_fault1(), to do either 143 * file- or vnode-based I/O calls. 144 */ 145 struct vn_io_fault_args { 146 enum { 147 VN_IO_FAULT_FOP, 148 VN_IO_FAULT_VOP 149 } kind; 150 struct ucred *cred; 151 int flags; 152 union { 153 struct fop_args_tag { 154 struct file *fp; 155 fo_rdwr_t *doio; 156 } fop_args; 157 struct vop_args_tag { 158 struct vnode *vp; 159 } vop_args; 160 } args; 161 }; 162 163 static int vn_io_fault1(struct vnode *vp, struct uio *uio, 164 struct vn_io_fault_args *args, struct thread *td); 165 166 int 167 vn_open(ndp, flagp, cmode, fp) 168 struct nameidata *ndp; 169 int *flagp, cmode; 170 struct file *fp; 171 { 172 struct thread *td = ndp->ni_cnd.cn_thread; 173 174 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp)); 175 } 176 177 /* 178 * Common code for vnode open operations via a name lookup. 179 * Lookup the vnode and invoke VOP_CREATE if needed. 180 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine. 181 * 182 * Note that this does NOT free nameidata for the successful case, 183 * due to the NDINIT being done elsewhere. 184 */ 185 int 186 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags, 187 struct ucred *cred, struct file *fp) 188 { 189 struct vnode *vp; 190 struct mount *mp; 191 struct thread *td = ndp->ni_cnd.cn_thread; 192 struct vattr vat; 193 struct vattr *vap = &vat; 194 int fmode, error; 195 196 restart: 197 fmode = *flagp; 198 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT | 199 O_EXCL | O_DIRECTORY)) 200 return (EINVAL); 201 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) { 202 ndp->ni_cnd.cn_nameiop = CREATE; 203 /* 204 * Set NOCACHE to avoid flushing the cache when 205 * rolling in many files at once. 206 */ 207 ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF | NOCACHE; 208 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0) 209 ndp->ni_cnd.cn_flags |= FOLLOW; 210 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 211 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 212 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 213 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 214 bwillwrite(); 215 if ((error = namei(ndp)) != 0) 216 return (error); 217 if (ndp->ni_vp == NULL) { 218 VATTR_NULL(vap); 219 vap->va_type = VREG; 220 vap->va_mode = cmode; 221 if (fmode & O_EXCL) 222 vap->va_vaflags |= VA_EXCLUSIVE; 223 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) { 224 NDFREE(ndp, NDF_ONLY_PNBUF); 225 vput(ndp->ni_dvp); 226 if ((error = vn_start_write(NULL, &mp, 227 V_XSLEEP | PCATCH)) != 0) 228 return (error); 229 goto restart; 230 } 231 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0) 232 ndp->ni_cnd.cn_flags |= MAKEENTRY; 233 #ifdef MAC 234 error = mac_vnode_check_create(cred, ndp->ni_dvp, 235 &ndp->ni_cnd, vap); 236 if (error == 0) 237 #endif 238 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp, 239 &ndp->ni_cnd, vap); 240 vput(ndp->ni_dvp); 241 vn_finished_write(mp); 242 if (error) { 243 NDFREE(ndp, NDF_ONLY_PNBUF); 244 return (error); 245 } 246 fmode &= ~O_TRUNC; 247 vp = ndp->ni_vp; 248 } else { 249 if (ndp->ni_dvp == ndp->ni_vp) 250 vrele(ndp->ni_dvp); 251 else 252 vput(ndp->ni_dvp); 253 ndp->ni_dvp = NULL; 254 vp = ndp->ni_vp; 255 if (fmode & O_EXCL) { 256 error = EEXIST; 257 goto bad; 258 } 259 fmode &= ~O_CREAT; 260 } 261 } else { 262 ndp->ni_cnd.cn_nameiop = LOOKUP; 263 ndp->ni_cnd.cn_flags = ISOPEN | 264 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF; 265 if (!(fmode & FWRITE)) 266 ndp->ni_cnd.cn_flags |= LOCKSHARED; 267 if (!(vn_open_flags & VN_OPEN_NOAUDIT)) 268 ndp->ni_cnd.cn_flags |= AUDITVNODE1; 269 if (vn_open_flags & VN_OPEN_NOCAPCHECK) 270 ndp->ni_cnd.cn_flags |= NOCAPCHECK; 271 if ((error = namei(ndp)) != 0) 272 return (error); 273 vp = ndp->ni_vp; 274 } 275 error = vn_open_vnode(vp, fmode, cred, td, fp); 276 if (error) 277 goto bad; 278 *flagp = fmode; 279 return (0); 280 bad: 281 NDFREE(ndp, NDF_ONLY_PNBUF); 282 vput(vp); 283 *flagp = fmode; 284 ndp->ni_vp = NULL; 285 return (error); 286 } 287 288 /* 289 * Common code for vnode open operations once a vnode is located. 290 * Check permissions, and call the VOP_OPEN routine. 291 */ 292 int 293 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred, 294 struct thread *td, struct file *fp) 295 { 296 struct mount *mp; 297 accmode_t accmode; 298 struct flock lf; 299 int error, have_flock, lock_flags, type; 300 301 if (vp->v_type == VLNK) 302 return (EMLINK); 303 if (vp->v_type == VSOCK) 304 return (EOPNOTSUPP); 305 if (vp->v_type != VDIR && fmode & O_DIRECTORY) 306 return (ENOTDIR); 307 accmode = 0; 308 if (fmode & (FWRITE | O_TRUNC)) { 309 if (vp->v_type == VDIR) 310 return (EISDIR); 311 accmode |= VWRITE; 312 } 313 if (fmode & FREAD) 314 accmode |= VREAD; 315 if (fmode & FEXEC) 316 accmode |= VEXEC; 317 if ((fmode & O_APPEND) && (fmode & FWRITE)) 318 accmode |= VAPPEND; 319 #ifdef MAC 320 if (fmode & O_CREAT) 321 accmode |= VCREAT; 322 if (fmode & O_VERIFY) 323 accmode |= VVERIFY; 324 error = mac_vnode_check_open(cred, vp, accmode); 325 if (error) 326 return (error); 327 328 accmode &= ~(VCREAT | VVERIFY); 329 #endif 330 if ((fmode & O_CREAT) == 0) { 331 if (accmode & VWRITE) { 332 error = vn_writechk(vp); 333 if (error) 334 return (error); 335 } 336 if (accmode) { 337 error = VOP_ACCESS(vp, accmode, cred, td); 338 if (error) 339 return (error); 340 } 341 } 342 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE) 343 vn_lock(vp, LK_UPGRADE | LK_RETRY); 344 if ((error = VOP_OPEN(vp, fmode, cred, td, fp)) != 0) 345 return (error); 346 347 if (fmode & (O_EXLOCK | O_SHLOCK)) { 348 KASSERT(fp != NULL, ("open with flock requires fp")); 349 lock_flags = VOP_ISLOCKED(vp); 350 VOP_UNLOCK(vp, 0); 351 lf.l_whence = SEEK_SET; 352 lf.l_start = 0; 353 lf.l_len = 0; 354 if (fmode & O_EXLOCK) 355 lf.l_type = F_WRLCK; 356 else 357 lf.l_type = F_RDLCK; 358 type = F_FLOCK; 359 if ((fmode & FNONBLOCK) == 0) 360 type |= F_WAIT; 361 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type); 362 have_flock = (error == 0); 363 vn_lock(vp, lock_flags | LK_RETRY); 364 if (error == 0 && vp->v_iflag & VI_DOOMED) 365 error = ENOENT; 366 /* 367 * Another thread might have used this vnode as an 368 * executable while the vnode lock was dropped. 369 * Ensure the vnode is still able to be opened for 370 * writing after the lock has been obtained. 371 */ 372 if (error == 0 && accmode & VWRITE) 373 error = vn_writechk(vp); 374 if (error) { 375 VOP_UNLOCK(vp, 0); 376 if (have_flock) { 377 lf.l_whence = SEEK_SET; 378 lf.l_start = 0; 379 lf.l_len = 0; 380 lf.l_type = F_UNLCK; 381 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, 382 F_FLOCK); 383 } 384 vn_start_write(vp, &mp, V_WAIT); 385 vn_lock(vp, lock_flags | LK_RETRY); 386 (void)VOP_CLOSE(vp, fmode, cred, td); 387 vn_finished_write(mp); 388 /* Prevent second close from fdrop()->vn_close(). */ 389 if (fp != NULL) 390 fp->f_ops= &badfileops; 391 return (error); 392 } 393 fp->f_flag |= FHASLOCK; 394 } 395 if (fmode & FWRITE) { 396 VOP_ADD_WRITECOUNT(vp, 1); 397 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d", 398 __func__, vp, vp->v_writecount); 399 } 400 ASSERT_VOP_LOCKED(vp, "vn_open_vnode"); 401 return (0); 402 } 403 404 /* 405 * Check for write permissions on the specified vnode. 406 * Prototype text segments cannot be written. 407 */ 408 int 409 vn_writechk(vp) 410 register struct vnode *vp; 411 { 412 413 ASSERT_VOP_LOCKED(vp, "vn_writechk"); 414 /* 415 * If there's shared text associated with 416 * the vnode, try to free it up once. If 417 * we fail, we can't allow writing. 418 */ 419 if (VOP_IS_TEXT(vp)) 420 return (ETXTBSY); 421 422 return (0); 423 } 424 425 /* 426 * Vnode close call 427 */ 428 int 429 vn_close(vp, flags, file_cred, td) 430 register struct vnode *vp; 431 int flags; 432 struct ucred *file_cred; 433 struct thread *td; 434 { 435 struct mount *mp; 436 int error, lock_flags; 437 438 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 && 439 MNT_EXTENDED_SHARED(vp->v_mount)) 440 lock_flags = LK_SHARED; 441 else 442 lock_flags = LK_EXCLUSIVE; 443 444 vn_start_write(vp, &mp, V_WAIT); 445 vn_lock(vp, lock_flags | LK_RETRY); 446 if (flags & FWRITE) { 447 VNASSERT(vp->v_writecount > 0, vp, 448 ("vn_close: negative writecount")); 449 VOP_ADD_WRITECOUNT(vp, -1); 450 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d", 451 __func__, vp, vp->v_writecount); 452 } 453 error = VOP_CLOSE(vp, flags, file_cred, td); 454 vput(vp); 455 vn_finished_write(mp); 456 return (error); 457 } 458 459 /* 460 * Heuristic to detect sequential operation. 461 */ 462 static int 463 sequential_heuristic(struct uio *uio, struct file *fp) 464 { 465 466 ASSERT_VOP_LOCKED(fp->f_vnode, __func__); 467 if (fp->f_flag & FRDAHEAD) 468 return (fp->f_seqcount << IO_SEQSHIFT); 469 470 /* 471 * Offset 0 is handled specially. open() sets f_seqcount to 1 so 472 * that the first I/O is normally considered to be slightly 473 * sequential. Seeking to offset 0 doesn't change sequentiality 474 * unless previous seeks have reduced f_seqcount to 0, in which 475 * case offset 0 is not special. 476 */ 477 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) || 478 uio->uio_offset == fp->f_nextoff) { 479 /* 480 * f_seqcount is in units of fixed-size blocks so that it 481 * depends mainly on the amount of sequential I/O and not 482 * much on the number of sequential I/O's. The fixed size 483 * of 16384 is hard-coded here since it is (not quite) just 484 * a magic size that works well here. This size is more 485 * closely related to the best I/O size for real disks than 486 * to any block size used by software. 487 */ 488 fp->f_seqcount += howmany(uio->uio_resid, 16384); 489 if (fp->f_seqcount > IO_SEQMAX) 490 fp->f_seqcount = IO_SEQMAX; 491 return (fp->f_seqcount << IO_SEQSHIFT); 492 } 493 494 /* Not sequential. Quickly draw-down sequentiality. */ 495 if (fp->f_seqcount > 1) 496 fp->f_seqcount = 1; 497 else 498 fp->f_seqcount = 0; 499 return (0); 500 } 501 502 /* 503 * Package up an I/O request on a vnode into a uio and do it. 504 */ 505 int 506 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset, 507 enum uio_seg segflg, int ioflg, struct ucred *active_cred, 508 struct ucred *file_cred, ssize_t *aresid, struct thread *td) 509 { 510 struct uio auio; 511 struct iovec aiov; 512 struct mount *mp; 513 struct ucred *cred; 514 void *rl_cookie; 515 struct vn_io_fault_args args; 516 int error, lock_flags; 517 518 auio.uio_iov = &aiov; 519 auio.uio_iovcnt = 1; 520 aiov.iov_base = base; 521 aiov.iov_len = len; 522 auio.uio_resid = len; 523 auio.uio_offset = offset; 524 auio.uio_segflg = segflg; 525 auio.uio_rw = rw; 526 auio.uio_td = td; 527 error = 0; 528 529 if ((ioflg & IO_NODELOCKED) == 0) { 530 if ((ioflg & IO_RANGELOCKED) == 0) { 531 if (rw == UIO_READ) { 532 rl_cookie = vn_rangelock_rlock(vp, offset, 533 offset + len); 534 } else { 535 rl_cookie = vn_rangelock_wlock(vp, offset, 536 offset + len); 537 } 538 } else 539 rl_cookie = NULL; 540 mp = NULL; 541 if (rw == UIO_WRITE) { 542 if (vp->v_type != VCHR && 543 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) 544 != 0) 545 goto out; 546 if (MNT_SHARED_WRITES(mp) || 547 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount))) 548 lock_flags = LK_SHARED; 549 else 550 lock_flags = LK_EXCLUSIVE; 551 } else 552 lock_flags = LK_SHARED; 553 vn_lock(vp, lock_flags | LK_RETRY); 554 } else 555 rl_cookie = NULL; 556 557 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 558 #ifdef MAC 559 if ((ioflg & IO_NOMACCHECK) == 0) { 560 if (rw == UIO_READ) 561 error = mac_vnode_check_read(active_cred, file_cred, 562 vp); 563 else 564 error = mac_vnode_check_write(active_cred, file_cred, 565 vp); 566 } 567 #endif 568 if (error == 0) { 569 if (file_cred != NULL) 570 cred = file_cred; 571 else 572 cred = active_cred; 573 if (do_vn_io_fault(vp, &auio)) { 574 args.kind = VN_IO_FAULT_VOP; 575 args.cred = cred; 576 args.flags = ioflg; 577 args.args.vop_args.vp = vp; 578 error = vn_io_fault1(vp, &auio, &args, td); 579 } else if (rw == UIO_READ) { 580 error = VOP_READ(vp, &auio, ioflg, cred); 581 } else /* if (rw == UIO_WRITE) */ { 582 error = VOP_WRITE(vp, &auio, ioflg, cred); 583 } 584 } 585 if (aresid) 586 *aresid = auio.uio_resid; 587 else 588 if (auio.uio_resid && error == 0) 589 error = EIO; 590 if ((ioflg & IO_NODELOCKED) == 0) { 591 VOP_UNLOCK(vp, 0); 592 if (mp != NULL) 593 vn_finished_write(mp); 594 } 595 out: 596 if (rl_cookie != NULL) 597 vn_rangelock_unlock(vp, rl_cookie); 598 return (error); 599 } 600 601 /* 602 * Package up an I/O request on a vnode into a uio and do it. The I/O 603 * request is split up into smaller chunks and we try to avoid saturating 604 * the buffer cache while potentially holding a vnode locked, so we 605 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield() 606 * to give other processes a chance to lock the vnode (either other processes 607 * core'ing the same binary, or unrelated processes scanning the directory). 608 */ 609 int 610 vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred, 611 file_cred, aresid, td) 612 enum uio_rw rw; 613 struct vnode *vp; 614 void *base; 615 size_t len; 616 off_t offset; 617 enum uio_seg segflg; 618 int ioflg; 619 struct ucred *active_cred; 620 struct ucred *file_cred; 621 size_t *aresid; 622 struct thread *td; 623 { 624 int error = 0; 625 ssize_t iaresid; 626 627 do { 628 int chunk; 629 630 /* 631 * Force `offset' to a multiple of MAXBSIZE except possibly 632 * for the first chunk, so that filesystems only need to 633 * write full blocks except possibly for the first and last 634 * chunks. 635 */ 636 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE; 637 638 if (chunk > len) 639 chunk = len; 640 if (rw != UIO_READ && vp->v_type == VREG) 641 bwillwrite(); 642 iaresid = 0; 643 error = vn_rdwr(rw, vp, base, chunk, offset, segflg, 644 ioflg, active_cred, file_cred, &iaresid, td); 645 len -= chunk; /* aresid calc already includes length */ 646 if (error) 647 break; 648 offset += chunk; 649 base = (char *)base + chunk; 650 kern_yield(PRI_USER); 651 } while (len); 652 if (aresid) 653 *aresid = len + iaresid; 654 return (error); 655 } 656 657 off_t 658 foffset_lock(struct file *fp, int flags) 659 { 660 struct mtx *mtxp; 661 off_t res; 662 663 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 664 665 #if OFF_MAX <= LONG_MAX 666 /* 667 * Caller only wants the current f_offset value. Assume that 668 * the long and shorter integer types reads are atomic. 669 */ 670 if ((flags & FOF_NOLOCK) != 0) 671 return (fp->f_offset); 672 #endif 673 674 /* 675 * According to McKusick the vn lock was protecting f_offset here. 676 * It is now protected by the FOFFSET_LOCKED flag. 677 */ 678 mtxp = mtx_pool_find(mtxpool_sleep, fp); 679 mtx_lock(mtxp); 680 if ((flags & FOF_NOLOCK) == 0) { 681 while (fp->f_vnread_flags & FOFFSET_LOCKED) { 682 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING; 683 msleep(&fp->f_vnread_flags, mtxp, PUSER -1, 684 "vofflock", 0); 685 } 686 fp->f_vnread_flags |= FOFFSET_LOCKED; 687 } 688 res = fp->f_offset; 689 mtx_unlock(mtxp); 690 return (res); 691 } 692 693 void 694 foffset_unlock(struct file *fp, off_t val, int flags) 695 { 696 struct mtx *mtxp; 697 698 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed")); 699 700 #if OFF_MAX <= LONG_MAX 701 if ((flags & FOF_NOLOCK) != 0) { 702 if ((flags & FOF_NOUPDATE) == 0) 703 fp->f_offset = val; 704 if ((flags & FOF_NEXTOFF) != 0) 705 fp->f_nextoff = val; 706 return; 707 } 708 #endif 709 710 mtxp = mtx_pool_find(mtxpool_sleep, fp); 711 mtx_lock(mtxp); 712 if ((flags & FOF_NOUPDATE) == 0) 713 fp->f_offset = val; 714 if ((flags & FOF_NEXTOFF) != 0) 715 fp->f_nextoff = val; 716 if ((flags & FOF_NOLOCK) == 0) { 717 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0, 718 ("Lost FOFFSET_LOCKED")); 719 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING) 720 wakeup(&fp->f_vnread_flags); 721 fp->f_vnread_flags = 0; 722 } 723 mtx_unlock(mtxp); 724 } 725 726 void 727 foffset_lock_uio(struct file *fp, struct uio *uio, int flags) 728 { 729 730 if ((flags & FOF_OFFSET) == 0) 731 uio->uio_offset = foffset_lock(fp, flags); 732 } 733 734 void 735 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags) 736 { 737 738 if ((flags & FOF_OFFSET) == 0) 739 foffset_unlock(fp, uio->uio_offset, flags); 740 } 741 742 static int 743 get_advice(struct file *fp, struct uio *uio) 744 { 745 struct mtx *mtxp; 746 int ret; 747 748 ret = POSIX_FADV_NORMAL; 749 if (fp->f_advice == NULL) 750 return (ret); 751 752 mtxp = mtx_pool_find(mtxpool_sleep, fp); 753 mtx_lock(mtxp); 754 if (uio->uio_offset >= fp->f_advice->fa_start && 755 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end) 756 ret = fp->f_advice->fa_advice; 757 mtx_unlock(mtxp); 758 return (ret); 759 } 760 761 /* 762 * File table vnode read routine. 763 */ 764 static int 765 vn_read(fp, uio, active_cred, flags, td) 766 struct file *fp; 767 struct uio *uio; 768 struct ucred *active_cred; 769 int flags; 770 struct thread *td; 771 { 772 struct vnode *vp; 773 struct mtx *mtxp; 774 int error, ioflag; 775 int advice; 776 off_t offset, start, end; 777 778 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 779 uio->uio_td, td)); 780 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 781 vp = fp->f_vnode; 782 ioflag = 0; 783 if (fp->f_flag & FNONBLOCK) 784 ioflag |= IO_NDELAY; 785 if (fp->f_flag & O_DIRECT) 786 ioflag |= IO_DIRECT; 787 advice = get_advice(fp, uio); 788 vn_lock(vp, LK_SHARED | LK_RETRY); 789 790 switch (advice) { 791 case POSIX_FADV_NORMAL: 792 case POSIX_FADV_SEQUENTIAL: 793 case POSIX_FADV_NOREUSE: 794 ioflag |= sequential_heuristic(uio, fp); 795 break; 796 case POSIX_FADV_RANDOM: 797 /* Disable read-ahead for random I/O. */ 798 break; 799 } 800 offset = uio->uio_offset; 801 802 #ifdef MAC 803 error = mac_vnode_check_read(active_cred, fp->f_cred, vp); 804 if (error == 0) 805 #endif 806 error = VOP_READ(vp, uio, ioflag, fp->f_cred); 807 fp->f_nextoff = uio->uio_offset; 808 VOP_UNLOCK(vp, 0); 809 if (error == 0 && advice == POSIX_FADV_NOREUSE && 810 offset != uio->uio_offset) { 811 /* 812 * Use POSIX_FADV_DONTNEED to flush clean pages and 813 * buffers for the backing file after a 814 * POSIX_FADV_NOREUSE read(2). To optimize the common 815 * case of using POSIX_FADV_NOREUSE with sequential 816 * access, track the previous implicit DONTNEED 817 * request and grow this request to include the 818 * current read(2) in addition to the previous 819 * DONTNEED. With purely sequential access this will 820 * cause the DONTNEED requests to continously grow to 821 * cover all of the previously read regions of the 822 * file. This allows filesystem blocks that are 823 * accessed by multiple calls to read(2) to be flushed 824 * once the last read(2) finishes. 825 */ 826 start = offset; 827 end = uio->uio_offset - 1; 828 mtxp = mtx_pool_find(mtxpool_sleep, fp); 829 mtx_lock(mtxp); 830 if (fp->f_advice != NULL && 831 fp->f_advice->fa_advice == POSIX_FADV_NOREUSE) { 832 if (start != 0 && fp->f_advice->fa_prevend + 1 == start) 833 start = fp->f_advice->fa_prevstart; 834 else if (fp->f_advice->fa_prevstart != 0 && 835 fp->f_advice->fa_prevstart == end + 1) 836 end = fp->f_advice->fa_prevend; 837 fp->f_advice->fa_prevstart = start; 838 fp->f_advice->fa_prevend = end; 839 } 840 mtx_unlock(mtxp); 841 error = VOP_ADVISE(vp, start, end, POSIX_FADV_DONTNEED); 842 } 843 return (error); 844 } 845 846 /* 847 * File table vnode write routine. 848 */ 849 static int 850 vn_write(fp, uio, active_cred, flags, td) 851 struct file *fp; 852 struct uio *uio; 853 struct ucred *active_cred; 854 int flags; 855 struct thread *td; 856 { 857 struct vnode *vp; 858 struct mount *mp; 859 struct mtx *mtxp; 860 int error, ioflag, lock_flags; 861 int advice; 862 off_t offset, start, end; 863 864 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p", 865 uio->uio_td, td)); 866 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET")); 867 vp = fp->f_vnode; 868 if (vp->v_type == VREG) 869 bwillwrite(); 870 ioflag = IO_UNIT; 871 if (vp->v_type == VREG && (fp->f_flag & O_APPEND)) 872 ioflag |= IO_APPEND; 873 if (fp->f_flag & FNONBLOCK) 874 ioflag |= IO_NDELAY; 875 if (fp->f_flag & O_DIRECT) 876 ioflag |= IO_DIRECT; 877 if ((fp->f_flag & O_FSYNC) || 878 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS))) 879 ioflag |= IO_SYNC; 880 mp = NULL; 881 if (vp->v_type != VCHR && 882 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0) 883 goto unlock; 884 885 advice = get_advice(fp, uio); 886 887 if (MNT_SHARED_WRITES(mp) || 888 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) { 889 lock_flags = LK_SHARED; 890 } else { 891 lock_flags = LK_EXCLUSIVE; 892 } 893 894 vn_lock(vp, lock_flags | LK_RETRY); 895 switch (advice) { 896 case POSIX_FADV_NORMAL: 897 case POSIX_FADV_SEQUENTIAL: 898 case POSIX_FADV_NOREUSE: 899 ioflag |= sequential_heuristic(uio, fp); 900 break; 901 case POSIX_FADV_RANDOM: 902 /* XXX: Is this correct? */ 903 break; 904 } 905 offset = uio->uio_offset; 906 907 #ifdef MAC 908 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 909 if (error == 0) 910 #endif 911 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred); 912 fp->f_nextoff = uio->uio_offset; 913 VOP_UNLOCK(vp, 0); 914 if (vp->v_type != VCHR) 915 vn_finished_write(mp); 916 if (error == 0 && advice == POSIX_FADV_NOREUSE && 917 offset != uio->uio_offset) { 918 /* 919 * Use POSIX_FADV_DONTNEED to flush clean pages and 920 * buffers for the backing file after a 921 * POSIX_FADV_NOREUSE write(2). To optimize the 922 * common case of using POSIX_FADV_NOREUSE with 923 * sequential access, track the previous implicit 924 * DONTNEED request and grow this request to include 925 * the current write(2) in addition to the previous 926 * DONTNEED. With purely sequential access this will 927 * cause the DONTNEED requests to continously grow to 928 * cover all of the previously written regions of the 929 * file. 930 * 931 * Note that the blocks just written are almost 932 * certainly still dirty, so this only works when 933 * VOP_ADVISE() calls from subsequent writes push out 934 * the data written by this write(2) once the backing 935 * buffers are clean. However, as compared to forcing 936 * IO_DIRECT, this gives much saner behavior. Write 937 * clustering is still allowed, and clean pages are 938 * merely moved to the cache page queue rather than 939 * outright thrown away. This means a subsequent 940 * read(2) can still avoid hitting the disk if the 941 * pages have not been reclaimed. 942 * 943 * This does make POSIX_FADV_NOREUSE largely useless 944 * with non-sequential access. However, sequential 945 * access is the more common use case and the flag is 946 * merely advisory. 947 */ 948 start = offset; 949 end = uio->uio_offset - 1; 950 mtxp = mtx_pool_find(mtxpool_sleep, fp); 951 mtx_lock(mtxp); 952 if (fp->f_advice != NULL && 953 fp->f_advice->fa_advice == POSIX_FADV_NOREUSE) { 954 if (start != 0 && fp->f_advice->fa_prevend + 1 == start) 955 start = fp->f_advice->fa_prevstart; 956 else if (fp->f_advice->fa_prevstart != 0 && 957 fp->f_advice->fa_prevstart == end + 1) 958 end = fp->f_advice->fa_prevend; 959 fp->f_advice->fa_prevstart = start; 960 fp->f_advice->fa_prevend = end; 961 } 962 mtx_unlock(mtxp); 963 error = VOP_ADVISE(vp, start, end, POSIX_FADV_DONTNEED); 964 } 965 966 unlock: 967 return (error); 968 } 969 970 /* 971 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to 972 * prevent the following deadlock: 973 * 974 * Assume that the thread A reads from the vnode vp1 into userspace 975 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is 976 * currently not resident, then system ends up with the call chain 977 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] -> 978 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2) 979 * which establishes lock order vp1->vn_lock, then vp2->vn_lock. 980 * If, at the same time, thread B reads from vnode vp2 into buffer buf2 981 * backed by the pages of vnode vp1, and some page in buf2 is not 982 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock. 983 * 984 * To prevent the lock order reversal and deadlock, vn_io_fault() does 985 * not allow page faults to happen during VOP_READ() or VOP_WRITE(). 986 * Instead, it first tries to do the whole range i/o with pagefaults 987 * disabled. If all pages in the i/o buffer are resident and mapped, 988 * VOP will succeed (ignoring the genuine filesystem errors). 989 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do 990 * i/o in chunks, with all pages in the chunk prefaulted and held 991 * using vm_fault_quick_hold_pages(). 992 * 993 * Filesystems using this deadlock avoidance scheme should use the 994 * array of the held pages from uio, saved in the curthread->td_ma, 995 * instead of doing uiomove(). A helper function 996 * vn_io_fault_uiomove() converts uiomove request into 997 * uiomove_fromphys() over td_ma array. 998 * 999 * Since vnode locks do not cover the whole i/o anymore, rangelocks 1000 * make the current i/o request atomic with respect to other i/os and 1001 * truncations. 1002 */ 1003 1004 /* 1005 * Decode vn_io_fault_args and perform the corresponding i/o. 1006 */ 1007 static int 1008 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio, 1009 struct thread *td) 1010 { 1011 1012 switch (args->kind) { 1013 case VN_IO_FAULT_FOP: 1014 return ((args->args.fop_args.doio)(args->args.fop_args.fp, 1015 uio, args->cred, args->flags, td)); 1016 case VN_IO_FAULT_VOP: 1017 if (uio->uio_rw == UIO_READ) { 1018 return (VOP_READ(args->args.vop_args.vp, uio, 1019 args->flags, args->cred)); 1020 } else if (uio->uio_rw == UIO_WRITE) { 1021 return (VOP_WRITE(args->args.vop_args.vp, uio, 1022 args->flags, args->cred)); 1023 } 1024 break; 1025 } 1026 panic("vn_io_fault_doio: unknown kind of io %d %d", args->kind, 1027 uio->uio_rw); 1028 } 1029 1030 static int 1031 vn_io_fault_touch(char *base, const struct uio *uio) 1032 { 1033 int r; 1034 1035 r = fubyte(base); 1036 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1)) 1037 return (EFAULT); 1038 return (0); 1039 } 1040 1041 static int 1042 vn_io_fault_prefault_user(const struct uio *uio) 1043 { 1044 char *base; 1045 const struct iovec *iov; 1046 size_t len; 1047 ssize_t resid; 1048 int error, i; 1049 1050 KASSERT(uio->uio_segflg == UIO_USERSPACE, 1051 ("vn_io_fault_prefault userspace")); 1052 1053 error = i = 0; 1054 iov = uio->uio_iov; 1055 resid = uio->uio_resid; 1056 base = iov->iov_base; 1057 len = iov->iov_len; 1058 while (resid > 0) { 1059 error = vn_io_fault_touch(base, uio); 1060 if (error != 0) 1061 break; 1062 if (len < PAGE_SIZE) { 1063 if (len != 0) { 1064 error = vn_io_fault_touch(base + len - 1, uio); 1065 if (error != 0) 1066 break; 1067 resid -= len; 1068 } 1069 if (++i >= uio->uio_iovcnt) 1070 break; 1071 iov = uio->uio_iov + i; 1072 base = iov->iov_base; 1073 len = iov->iov_len; 1074 } else { 1075 len -= PAGE_SIZE; 1076 base += PAGE_SIZE; 1077 resid -= PAGE_SIZE; 1078 } 1079 } 1080 return (error); 1081 } 1082 1083 /* 1084 * Common code for vn_io_fault(), agnostic to the kind of i/o request. 1085 * Uses vn_io_fault_doio() to make the call to an actual i/o function. 1086 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request 1087 * into args and call vn_io_fault1() to handle faults during the user 1088 * mode buffer accesses. 1089 */ 1090 static int 1091 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args, 1092 struct thread *td) 1093 { 1094 vm_page_t ma[io_hold_cnt + 2]; 1095 struct uio *uio_clone, short_uio; 1096 struct iovec short_iovec[1]; 1097 vm_page_t *prev_td_ma; 1098 vm_prot_t prot; 1099 vm_offset_t addr, end; 1100 size_t len, resid; 1101 ssize_t adv; 1102 int error, cnt, save, saveheld, prev_td_ma_cnt; 1103 1104 if (vn_io_fault_prefault) { 1105 error = vn_io_fault_prefault_user(uio); 1106 if (error != 0) 1107 return (error); /* Or ignore ? */ 1108 } 1109 1110 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ; 1111 1112 /* 1113 * The UFS follows IO_UNIT directive and replays back both 1114 * uio_offset and uio_resid if an error is encountered during the 1115 * operation. But, since the iovec may be already advanced, 1116 * uio is still in an inconsistent state. 1117 * 1118 * Cache a copy of the original uio, which is advanced to the redo 1119 * point using UIO_NOCOPY below. 1120 */ 1121 uio_clone = cloneuio(uio); 1122 resid = uio->uio_resid; 1123 1124 short_uio.uio_segflg = UIO_USERSPACE; 1125 short_uio.uio_rw = uio->uio_rw; 1126 short_uio.uio_td = uio->uio_td; 1127 1128 save = vm_fault_disable_pagefaults(); 1129 error = vn_io_fault_doio(args, uio, td); 1130 if (error != EFAULT) 1131 goto out; 1132 1133 atomic_add_long(&vn_io_faults_cnt, 1); 1134 uio_clone->uio_segflg = UIO_NOCOPY; 1135 uiomove(NULL, resid - uio->uio_resid, uio_clone); 1136 uio_clone->uio_segflg = uio->uio_segflg; 1137 1138 saveheld = curthread_pflags_set(TDP_UIOHELD); 1139 prev_td_ma = td->td_ma; 1140 prev_td_ma_cnt = td->td_ma_cnt; 1141 1142 while (uio_clone->uio_resid != 0) { 1143 len = uio_clone->uio_iov->iov_len; 1144 if (len == 0) { 1145 KASSERT(uio_clone->uio_iovcnt >= 1, 1146 ("iovcnt underflow")); 1147 uio_clone->uio_iov++; 1148 uio_clone->uio_iovcnt--; 1149 continue; 1150 } 1151 if (len > io_hold_cnt * PAGE_SIZE) 1152 len = io_hold_cnt * PAGE_SIZE; 1153 addr = (uintptr_t)uio_clone->uio_iov->iov_base; 1154 end = round_page(addr + len); 1155 if (end < addr) { 1156 error = EFAULT; 1157 break; 1158 } 1159 cnt = atop(end - trunc_page(addr)); 1160 /* 1161 * A perfectly misaligned address and length could cause 1162 * both the start and the end of the chunk to use partial 1163 * page. +2 accounts for such a situation. 1164 */ 1165 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map, 1166 addr, len, prot, ma, io_hold_cnt + 2); 1167 if (cnt == -1) { 1168 error = EFAULT; 1169 break; 1170 } 1171 short_uio.uio_iov = &short_iovec[0]; 1172 short_iovec[0].iov_base = (void *)addr; 1173 short_uio.uio_iovcnt = 1; 1174 short_uio.uio_resid = short_iovec[0].iov_len = len; 1175 short_uio.uio_offset = uio_clone->uio_offset; 1176 td->td_ma = ma; 1177 td->td_ma_cnt = cnt; 1178 1179 error = vn_io_fault_doio(args, &short_uio, td); 1180 vm_page_unhold_pages(ma, cnt); 1181 adv = len - short_uio.uio_resid; 1182 1183 uio_clone->uio_iov->iov_base = 1184 (char *)uio_clone->uio_iov->iov_base + adv; 1185 uio_clone->uio_iov->iov_len -= adv; 1186 uio_clone->uio_resid -= adv; 1187 uio_clone->uio_offset += adv; 1188 1189 uio->uio_resid -= adv; 1190 uio->uio_offset += adv; 1191 1192 if (error != 0 || adv == 0) 1193 break; 1194 } 1195 td->td_ma = prev_td_ma; 1196 td->td_ma_cnt = prev_td_ma_cnt; 1197 curthread_pflags_restore(saveheld); 1198 out: 1199 vm_fault_enable_pagefaults(save); 1200 free(uio_clone, M_IOV); 1201 return (error); 1202 } 1203 1204 static int 1205 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, 1206 int flags, struct thread *td) 1207 { 1208 fo_rdwr_t *doio; 1209 struct vnode *vp; 1210 void *rl_cookie; 1211 struct vn_io_fault_args args; 1212 int error; 1213 1214 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; 1215 vp = fp->f_vnode; 1216 foffset_lock_uio(fp, uio, flags); 1217 if (do_vn_io_fault(vp, uio)) { 1218 args.kind = VN_IO_FAULT_FOP; 1219 args.args.fop_args.fp = fp; 1220 args.args.fop_args.doio = doio; 1221 args.cred = active_cred; 1222 args.flags = flags | FOF_OFFSET; 1223 if (uio->uio_rw == UIO_READ) { 1224 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset, 1225 uio->uio_offset + uio->uio_resid); 1226 } else if ((fp->f_flag & O_APPEND) != 0 || 1227 (flags & FOF_OFFSET) == 0) { 1228 /* For appenders, punt and lock the whole range. */ 1229 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1230 } else { 1231 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset, 1232 uio->uio_offset + uio->uio_resid); 1233 } 1234 error = vn_io_fault1(vp, uio, &args, td); 1235 vn_rangelock_unlock(vp, rl_cookie); 1236 } else { 1237 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td); 1238 } 1239 foffset_unlock_uio(fp, uio, flags); 1240 return (error); 1241 } 1242 1243 /* 1244 * Helper function to perform the requested uiomove operation using 1245 * the held pages for io->uio_iov[0].iov_base buffer instead of 1246 * copyin/copyout. Access to the pages with uiomove_fromphys() 1247 * instead of iov_base prevents page faults that could occur due to 1248 * pmap_collect() invalidating the mapping created by 1249 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or 1250 * object cleanup revoking the write access from page mappings. 1251 * 1252 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove() 1253 * instead of plain uiomove(). 1254 */ 1255 int 1256 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio) 1257 { 1258 struct uio transp_uio; 1259 struct iovec transp_iov[1]; 1260 struct thread *td; 1261 size_t adv; 1262 int error, pgadv; 1263 1264 td = curthread; 1265 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1266 uio->uio_segflg != UIO_USERSPACE) 1267 return (uiomove(data, xfersize, uio)); 1268 1269 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1270 transp_iov[0].iov_base = data; 1271 transp_uio.uio_iov = &transp_iov[0]; 1272 transp_uio.uio_iovcnt = 1; 1273 if (xfersize > uio->uio_resid) 1274 xfersize = uio->uio_resid; 1275 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize; 1276 transp_uio.uio_offset = 0; 1277 transp_uio.uio_segflg = UIO_SYSSPACE; 1278 /* 1279 * Since transp_iov points to data, and td_ma page array 1280 * corresponds to original uio->uio_iov, we need to invert the 1281 * direction of the i/o operation as passed to 1282 * uiomove_fromphys(). 1283 */ 1284 switch (uio->uio_rw) { 1285 case UIO_WRITE: 1286 transp_uio.uio_rw = UIO_READ; 1287 break; 1288 case UIO_READ: 1289 transp_uio.uio_rw = UIO_WRITE; 1290 break; 1291 } 1292 transp_uio.uio_td = uio->uio_td; 1293 error = uiomove_fromphys(td->td_ma, 1294 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK, 1295 xfersize, &transp_uio); 1296 adv = xfersize - transp_uio.uio_resid; 1297 pgadv = 1298 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) - 1299 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT); 1300 td->td_ma += pgadv; 1301 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1302 pgadv)); 1303 td->td_ma_cnt -= pgadv; 1304 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv; 1305 uio->uio_iov->iov_len -= adv; 1306 uio->uio_resid -= adv; 1307 uio->uio_offset += adv; 1308 return (error); 1309 } 1310 1311 int 1312 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize, 1313 struct uio *uio) 1314 { 1315 struct thread *td; 1316 vm_offset_t iov_base; 1317 int cnt, pgadv; 1318 1319 td = curthread; 1320 if ((td->td_pflags & TDP_UIOHELD) == 0 || 1321 uio->uio_segflg != UIO_USERSPACE) 1322 return (uiomove_fromphys(ma, offset, xfersize, uio)); 1323 1324 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt)); 1325 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize; 1326 iov_base = (vm_offset_t)uio->uio_iov->iov_base; 1327 switch (uio->uio_rw) { 1328 case UIO_WRITE: 1329 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma, 1330 offset, cnt); 1331 break; 1332 case UIO_READ: 1333 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK, 1334 cnt); 1335 break; 1336 } 1337 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT); 1338 td->td_ma += pgadv; 1339 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt, 1340 pgadv)); 1341 td->td_ma_cnt -= pgadv; 1342 uio->uio_iov->iov_base = (char *)(iov_base + cnt); 1343 uio->uio_iov->iov_len -= cnt; 1344 uio->uio_resid -= cnt; 1345 uio->uio_offset += cnt; 1346 return (0); 1347 } 1348 1349 1350 /* 1351 * File table truncate routine. 1352 */ 1353 static int 1354 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1355 struct thread *td) 1356 { 1357 struct vattr vattr; 1358 struct mount *mp; 1359 struct vnode *vp; 1360 void *rl_cookie; 1361 int error; 1362 1363 vp = fp->f_vnode; 1364 1365 /* 1366 * Lock the whole range for truncation. Otherwise split i/o 1367 * might happen partly before and partly after the truncation. 1368 */ 1369 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); 1370 error = vn_start_write(vp, &mp, V_WAIT | PCATCH); 1371 if (error) 1372 goto out1; 1373 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1374 if (vp->v_type == VDIR) { 1375 error = EISDIR; 1376 goto out; 1377 } 1378 #ifdef MAC 1379 error = mac_vnode_check_write(active_cred, fp->f_cred, vp); 1380 if (error) 1381 goto out; 1382 #endif 1383 error = vn_writechk(vp); 1384 if (error == 0) { 1385 VATTR_NULL(&vattr); 1386 vattr.va_size = length; 1387 error = VOP_SETATTR(vp, &vattr, fp->f_cred); 1388 } 1389 out: 1390 VOP_UNLOCK(vp, 0); 1391 vn_finished_write(mp); 1392 out1: 1393 vn_rangelock_unlock(vp, rl_cookie); 1394 return (error); 1395 } 1396 1397 /* 1398 * File table vnode stat routine. 1399 */ 1400 static int 1401 vn_statfile(fp, sb, active_cred, td) 1402 struct file *fp; 1403 struct stat *sb; 1404 struct ucred *active_cred; 1405 struct thread *td; 1406 { 1407 struct vnode *vp = fp->f_vnode; 1408 int error; 1409 1410 vn_lock(vp, LK_SHARED | LK_RETRY); 1411 error = vn_stat(vp, sb, active_cred, fp->f_cred, td); 1412 VOP_UNLOCK(vp, 0); 1413 1414 return (error); 1415 } 1416 1417 /* 1418 * Stat a vnode; implementation for the stat syscall 1419 */ 1420 int 1421 vn_stat(vp, sb, active_cred, file_cred, td) 1422 struct vnode *vp; 1423 register struct stat *sb; 1424 struct ucred *active_cred; 1425 struct ucred *file_cred; 1426 struct thread *td; 1427 { 1428 struct vattr vattr; 1429 register struct vattr *vap; 1430 int error; 1431 u_short mode; 1432 1433 #ifdef MAC 1434 error = mac_vnode_check_stat(active_cred, file_cred, vp); 1435 if (error) 1436 return (error); 1437 #endif 1438 1439 vap = &vattr; 1440 1441 /* 1442 * Initialize defaults for new and unusual fields, so that file 1443 * systems which don't support these fields don't need to know 1444 * about them. 1445 */ 1446 vap->va_birthtime.tv_sec = -1; 1447 vap->va_birthtime.tv_nsec = 0; 1448 vap->va_fsid = VNOVAL; 1449 vap->va_rdev = NODEV; 1450 1451 error = VOP_GETATTR(vp, vap, active_cred); 1452 if (error) 1453 return (error); 1454 1455 /* 1456 * Zero the spare stat fields 1457 */ 1458 bzero(sb, sizeof *sb); 1459 1460 /* 1461 * Copy from vattr table 1462 */ 1463 if (vap->va_fsid != VNOVAL) 1464 sb->st_dev = vap->va_fsid; 1465 else 1466 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0]; 1467 sb->st_ino = vap->va_fileid; 1468 mode = vap->va_mode; 1469 switch (vap->va_type) { 1470 case VREG: 1471 mode |= S_IFREG; 1472 break; 1473 case VDIR: 1474 mode |= S_IFDIR; 1475 break; 1476 case VBLK: 1477 mode |= S_IFBLK; 1478 break; 1479 case VCHR: 1480 mode |= S_IFCHR; 1481 break; 1482 case VLNK: 1483 mode |= S_IFLNK; 1484 break; 1485 case VSOCK: 1486 mode |= S_IFSOCK; 1487 break; 1488 case VFIFO: 1489 mode |= S_IFIFO; 1490 break; 1491 default: 1492 return (EBADF); 1493 }; 1494 sb->st_mode = mode; 1495 sb->st_nlink = vap->va_nlink; 1496 sb->st_uid = vap->va_uid; 1497 sb->st_gid = vap->va_gid; 1498 sb->st_rdev = vap->va_rdev; 1499 if (vap->va_size > OFF_MAX) 1500 return (EOVERFLOW); 1501 sb->st_size = vap->va_size; 1502 sb->st_atim = vap->va_atime; 1503 sb->st_mtim = vap->va_mtime; 1504 sb->st_ctim = vap->va_ctime; 1505 sb->st_birthtim = vap->va_birthtime; 1506 1507 /* 1508 * According to www.opengroup.org, the meaning of st_blksize is 1509 * "a filesystem-specific preferred I/O block size for this 1510 * object. In some filesystem types, this may vary from file 1511 * to file" 1512 * Use miminum/default of PAGE_SIZE (e.g. for VCHR). 1513 */ 1514 1515 sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize); 1516 1517 sb->st_flags = vap->va_flags; 1518 if (priv_check(td, PRIV_VFS_GENERATION)) 1519 sb->st_gen = 0; 1520 else 1521 sb->st_gen = vap->va_gen; 1522 1523 sb->st_blocks = vap->va_bytes / S_BLKSIZE; 1524 return (0); 1525 } 1526 1527 /* 1528 * File table vnode ioctl routine. 1529 */ 1530 static int 1531 vn_ioctl(fp, com, data, active_cred, td) 1532 struct file *fp; 1533 u_long com; 1534 void *data; 1535 struct ucred *active_cred; 1536 struct thread *td; 1537 { 1538 struct vattr vattr; 1539 struct vnode *vp; 1540 int error; 1541 1542 vp = fp->f_vnode; 1543 switch (vp->v_type) { 1544 case VDIR: 1545 case VREG: 1546 switch (com) { 1547 case FIONREAD: 1548 vn_lock(vp, LK_SHARED | LK_RETRY); 1549 error = VOP_GETATTR(vp, &vattr, active_cred); 1550 VOP_UNLOCK(vp, 0); 1551 if (error == 0) 1552 *(int *)data = vattr.va_size - fp->f_offset; 1553 return (error); 1554 case FIONBIO: 1555 case FIOASYNC: 1556 return (0); 1557 default: 1558 return (VOP_IOCTL(vp, com, data, fp->f_flag, 1559 active_cred, td)); 1560 } 1561 default: 1562 return (ENOTTY); 1563 } 1564 } 1565 1566 /* 1567 * File table vnode poll routine. 1568 */ 1569 static int 1570 vn_poll(fp, events, active_cred, td) 1571 struct file *fp; 1572 int events; 1573 struct ucred *active_cred; 1574 struct thread *td; 1575 { 1576 struct vnode *vp; 1577 int error; 1578 1579 vp = fp->f_vnode; 1580 #ifdef MAC 1581 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1582 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp); 1583 VOP_UNLOCK(vp, 0); 1584 if (!error) 1585 #endif 1586 1587 error = VOP_POLL(vp, events, fp->f_cred, td); 1588 return (error); 1589 } 1590 1591 /* 1592 * Acquire the requested lock and then check for validity. LK_RETRY 1593 * permits vn_lock to return doomed vnodes. 1594 */ 1595 int 1596 _vn_lock(struct vnode *vp, int flags, char *file, int line) 1597 { 1598 int error; 1599 1600 VNASSERT((flags & LK_TYPE_MASK) != 0, vp, 1601 ("vn_lock called with no locktype.")); 1602 do { 1603 #ifdef DEBUG_VFS_LOCKS 1604 KASSERT(vp->v_holdcnt != 0, 1605 ("vn_lock %p: zero hold count", vp)); 1606 #endif 1607 error = VOP_LOCK1(vp, flags, file, line); 1608 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */ 1609 KASSERT((flags & LK_RETRY) == 0 || error == 0, 1610 ("LK_RETRY set with incompatible flags (0x%x) or an error occured (%d)", 1611 flags, error)); 1612 /* 1613 * Callers specify LK_RETRY if they wish to get dead vnodes. 1614 * If RETRY is not set, we return ENOENT instead. 1615 */ 1616 if (error == 0 && vp->v_iflag & VI_DOOMED && 1617 (flags & LK_RETRY) == 0) { 1618 VOP_UNLOCK(vp, 0); 1619 error = ENOENT; 1620 break; 1621 } 1622 } while (flags & LK_RETRY && error != 0); 1623 return (error); 1624 } 1625 1626 /* 1627 * File table vnode close routine. 1628 */ 1629 static int 1630 vn_closefile(fp, td) 1631 struct file *fp; 1632 struct thread *td; 1633 { 1634 struct vnode *vp; 1635 struct flock lf; 1636 int error; 1637 1638 vp = fp->f_vnode; 1639 fp->f_ops = &badfileops; 1640 1641 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) 1642 vref(vp); 1643 1644 error = vn_close(vp, fp->f_flag, fp->f_cred, td); 1645 1646 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) { 1647 lf.l_whence = SEEK_SET; 1648 lf.l_start = 0; 1649 lf.l_len = 0; 1650 lf.l_type = F_UNLCK; 1651 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK); 1652 vrele(vp); 1653 } 1654 return (error); 1655 } 1656 1657 static bool 1658 vn_suspendable(struct mount *mp) 1659 { 1660 1661 return (mp->mnt_op->vfs_susp_clean != NULL); 1662 } 1663 1664 /* 1665 * Preparing to start a filesystem write operation. If the operation is 1666 * permitted, then we bump the count of operations in progress and 1667 * proceed. If a suspend request is in progress, we wait until the 1668 * suspension is over, and then proceed. 1669 */ 1670 static int 1671 vn_start_write_locked(struct mount *mp, int flags) 1672 { 1673 int error, mflags; 1674 1675 mtx_assert(MNT_MTX(mp), MA_OWNED); 1676 error = 0; 1677 1678 /* 1679 * Check on status of suspension. 1680 */ 1681 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 || 1682 mp->mnt_susp_owner != curthread) { 1683 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? 1684 (flags & PCATCH) : 0) | (PUSER - 1); 1685 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1686 if (flags & V_NOWAIT) { 1687 error = EWOULDBLOCK; 1688 goto unlock; 1689 } 1690 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags, 1691 "suspfs", 0); 1692 if (error) 1693 goto unlock; 1694 } 1695 } 1696 if (flags & V_XSLEEP) 1697 goto unlock; 1698 mp->mnt_writeopcount++; 1699 unlock: 1700 if (error != 0 || (flags & V_XSLEEP) != 0) 1701 MNT_REL(mp); 1702 MNT_IUNLOCK(mp); 1703 return (error); 1704 } 1705 1706 int 1707 vn_start_write(struct vnode *vp, struct mount **mpp, int flags) 1708 { 1709 struct mount *mp; 1710 int error; 1711 1712 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1713 ("V_MNTREF requires mp")); 1714 1715 error = 0; 1716 /* 1717 * If a vnode is provided, get and return the mount point that 1718 * to which it will write. 1719 */ 1720 if (vp != NULL) { 1721 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1722 *mpp = NULL; 1723 if (error != EOPNOTSUPP) 1724 return (error); 1725 return (0); 1726 } 1727 } 1728 if ((mp = *mpp) == NULL) 1729 return (0); 1730 1731 if (!vn_suspendable(mp)) { 1732 if (vp != NULL || (flags & V_MNTREF) != 0) 1733 vfs_rel(mp); 1734 return (0); 1735 } 1736 1737 /* 1738 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1739 * a vfs_ref(). 1740 * As long as a vnode is not provided we need to acquire a 1741 * refcount for the provided mountpoint too, in order to 1742 * emulate a vfs_ref(). 1743 */ 1744 MNT_ILOCK(mp); 1745 if (vp == NULL && (flags & V_MNTREF) == 0) 1746 MNT_REF(mp); 1747 1748 return (vn_start_write_locked(mp, flags)); 1749 } 1750 1751 /* 1752 * Secondary suspension. Used by operations such as vop_inactive 1753 * routines that are needed by the higher level functions. These 1754 * are allowed to proceed until all the higher level functions have 1755 * completed (indicated by mnt_writeopcount dropping to zero). At that 1756 * time, these operations are halted until the suspension is over. 1757 */ 1758 int 1759 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags) 1760 { 1761 struct mount *mp; 1762 int error; 1763 1764 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL), 1765 ("V_MNTREF requires mp")); 1766 1767 retry: 1768 if (vp != NULL) { 1769 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) { 1770 *mpp = NULL; 1771 if (error != EOPNOTSUPP) 1772 return (error); 1773 return (0); 1774 } 1775 } 1776 /* 1777 * If we are not suspended or have not yet reached suspended 1778 * mode, then let the operation proceed. 1779 */ 1780 if ((mp = *mpp) == NULL) 1781 return (0); 1782 1783 if (!vn_suspendable(mp)) { 1784 if (vp != NULL || (flags & V_MNTREF) != 0) 1785 vfs_rel(mp); 1786 return (0); 1787 } 1788 1789 /* 1790 * VOP_GETWRITEMOUNT() returns with the mp refcount held through 1791 * a vfs_ref(). 1792 * As long as a vnode is not provided we need to acquire a 1793 * refcount for the provided mountpoint too, in order to 1794 * emulate a vfs_ref(). 1795 */ 1796 MNT_ILOCK(mp); 1797 if (vp == NULL && (flags & V_MNTREF) == 0) 1798 MNT_REF(mp); 1799 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) { 1800 mp->mnt_secondary_writes++; 1801 mp->mnt_secondary_accwrites++; 1802 MNT_IUNLOCK(mp); 1803 return (0); 1804 } 1805 if (flags & V_NOWAIT) { 1806 MNT_REL(mp); 1807 MNT_IUNLOCK(mp); 1808 return (EWOULDBLOCK); 1809 } 1810 /* 1811 * Wait for the suspension to finish. 1812 */ 1813 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP | 1814 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0), 1815 "suspfs", 0); 1816 vfs_rel(mp); 1817 if (error == 0) 1818 goto retry; 1819 return (error); 1820 } 1821 1822 /* 1823 * Filesystem write operation has completed. If we are suspending and this 1824 * operation is the last one, notify the suspender that the suspension is 1825 * now in effect. 1826 */ 1827 void 1828 vn_finished_write(mp) 1829 struct mount *mp; 1830 { 1831 if (mp == NULL || !vn_suspendable(mp)) 1832 return; 1833 MNT_ILOCK(mp); 1834 MNT_REL(mp); 1835 mp->mnt_writeopcount--; 1836 if (mp->mnt_writeopcount < 0) 1837 panic("vn_finished_write: neg cnt"); 1838 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1839 mp->mnt_writeopcount <= 0) 1840 wakeup(&mp->mnt_writeopcount); 1841 MNT_IUNLOCK(mp); 1842 } 1843 1844 1845 /* 1846 * Filesystem secondary write operation has completed. If we are 1847 * suspending and this operation is the last one, notify the suspender 1848 * that the suspension is now in effect. 1849 */ 1850 void 1851 vn_finished_secondary_write(mp) 1852 struct mount *mp; 1853 { 1854 if (mp == NULL || !vn_suspendable(mp)) 1855 return; 1856 MNT_ILOCK(mp); 1857 MNT_REL(mp); 1858 mp->mnt_secondary_writes--; 1859 if (mp->mnt_secondary_writes < 0) 1860 panic("vn_finished_secondary_write: neg cnt"); 1861 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 && 1862 mp->mnt_secondary_writes <= 0) 1863 wakeup(&mp->mnt_secondary_writes); 1864 MNT_IUNLOCK(mp); 1865 } 1866 1867 1868 1869 /* 1870 * Request a filesystem to suspend write operations. 1871 */ 1872 int 1873 vfs_write_suspend(struct mount *mp, int flags) 1874 { 1875 int error; 1876 1877 MPASS(vn_suspendable(mp)); 1878 1879 MNT_ILOCK(mp); 1880 if (mp->mnt_susp_owner == curthread) { 1881 MNT_IUNLOCK(mp); 1882 return (EALREADY); 1883 } 1884 while (mp->mnt_kern_flag & MNTK_SUSPEND) 1885 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0); 1886 1887 /* 1888 * Unmount holds a write reference on the mount point. If we 1889 * own busy reference and drain for writers, we deadlock with 1890 * the reference draining in the unmount path. Callers of 1891 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if 1892 * vfs_busy() reference is owned and caller is not in the 1893 * unmount context. 1894 */ 1895 if ((flags & VS_SKIP_UNMOUNT) != 0 && 1896 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) { 1897 MNT_IUNLOCK(mp); 1898 return (EBUSY); 1899 } 1900 1901 mp->mnt_kern_flag |= MNTK_SUSPEND; 1902 mp->mnt_susp_owner = curthread; 1903 if (mp->mnt_writeopcount > 0) 1904 (void) msleep(&mp->mnt_writeopcount, 1905 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0); 1906 else 1907 MNT_IUNLOCK(mp); 1908 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0) 1909 vfs_write_resume(mp, 0); 1910 return (error); 1911 } 1912 1913 /* 1914 * Request a filesystem to resume write operations. 1915 */ 1916 void 1917 vfs_write_resume(struct mount *mp, int flags) 1918 { 1919 1920 MPASS(vn_suspendable(mp)); 1921 1922 MNT_ILOCK(mp); 1923 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) { 1924 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner")); 1925 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 | 1926 MNTK_SUSPENDED); 1927 mp->mnt_susp_owner = NULL; 1928 wakeup(&mp->mnt_writeopcount); 1929 wakeup(&mp->mnt_flag); 1930 curthread->td_pflags &= ~TDP_IGNSUSP; 1931 if ((flags & VR_START_WRITE) != 0) { 1932 MNT_REF(mp); 1933 mp->mnt_writeopcount++; 1934 } 1935 MNT_IUNLOCK(mp); 1936 if ((flags & VR_NO_SUSPCLR) == 0) 1937 VFS_SUSP_CLEAN(mp); 1938 } else if ((flags & VR_START_WRITE) != 0) { 1939 MNT_REF(mp); 1940 vn_start_write_locked(mp, 0); 1941 } else { 1942 MNT_IUNLOCK(mp); 1943 } 1944 } 1945 1946 /* 1947 * Helper loop around vfs_write_suspend() for filesystem unmount VFS 1948 * methods. 1949 */ 1950 int 1951 vfs_write_suspend_umnt(struct mount *mp) 1952 { 1953 int error; 1954 1955 MPASS(vn_suspendable(mp)); 1956 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0, 1957 ("vfs_write_suspend_umnt: recursed")); 1958 1959 /* dounmount() already called vn_start_write(). */ 1960 for (;;) { 1961 vn_finished_write(mp); 1962 error = vfs_write_suspend(mp, 0); 1963 if (error != 0) { 1964 vn_start_write(NULL, &mp, V_WAIT); 1965 return (error); 1966 } 1967 MNT_ILOCK(mp); 1968 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0) 1969 break; 1970 MNT_IUNLOCK(mp); 1971 vn_start_write(NULL, &mp, V_WAIT); 1972 } 1973 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2); 1974 wakeup(&mp->mnt_flag); 1975 MNT_IUNLOCK(mp); 1976 curthread->td_pflags |= TDP_IGNSUSP; 1977 return (0); 1978 } 1979 1980 /* 1981 * Implement kqueues for files by translating it to vnode operation. 1982 */ 1983 static int 1984 vn_kqfilter(struct file *fp, struct knote *kn) 1985 { 1986 1987 return (VOP_KQFILTER(fp->f_vnode, kn)); 1988 } 1989 1990 /* 1991 * Simplified in-kernel wrapper calls for extended attribute access. 1992 * Both calls pass in a NULL credential, authorizing as "kernel" access. 1993 * Set IO_NODELOCKED in ioflg if the vnode is already locked. 1994 */ 1995 int 1996 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace, 1997 const char *attrname, int *buflen, char *buf, struct thread *td) 1998 { 1999 struct uio auio; 2000 struct iovec iov; 2001 int error; 2002 2003 iov.iov_len = *buflen; 2004 iov.iov_base = buf; 2005 2006 auio.uio_iov = &iov; 2007 auio.uio_iovcnt = 1; 2008 auio.uio_rw = UIO_READ; 2009 auio.uio_segflg = UIO_SYSSPACE; 2010 auio.uio_td = td; 2011 auio.uio_offset = 0; 2012 auio.uio_resid = *buflen; 2013 2014 if ((ioflg & IO_NODELOCKED) == 0) 2015 vn_lock(vp, LK_SHARED | LK_RETRY); 2016 2017 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2018 2019 /* authorize attribute retrieval as kernel */ 2020 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL, 2021 td); 2022 2023 if ((ioflg & IO_NODELOCKED) == 0) 2024 VOP_UNLOCK(vp, 0); 2025 2026 if (error == 0) { 2027 *buflen = *buflen - auio.uio_resid; 2028 } 2029 2030 return (error); 2031 } 2032 2033 /* 2034 * XXX failure mode if partially written? 2035 */ 2036 int 2037 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace, 2038 const char *attrname, int buflen, char *buf, struct thread *td) 2039 { 2040 struct uio auio; 2041 struct iovec iov; 2042 struct mount *mp; 2043 int error; 2044 2045 iov.iov_len = buflen; 2046 iov.iov_base = buf; 2047 2048 auio.uio_iov = &iov; 2049 auio.uio_iovcnt = 1; 2050 auio.uio_rw = UIO_WRITE; 2051 auio.uio_segflg = UIO_SYSSPACE; 2052 auio.uio_td = td; 2053 auio.uio_offset = 0; 2054 auio.uio_resid = buflen; 2055 2056 if ((ioflg & IO_NODELOCKED) == 0) { 2057 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2058 return (error); 2059 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2060 } 2061 2062 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2063 2064 /* authorize attribute setting as kernel */ 2065 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td); 2066 2067 if ((ioflg & IO_NODELOCKED) == 0) { 2068 vn_finished_write(mp); 2069 VOP_UNLOCK(vp, 0); 2070 } 2071 2072 return (error); 2073 } 2074 2075 int 2076 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace, 2077 const char *attrname, struct thread *td) 2078 { 2079 struct mount *mp; 2080 int error; 2081 2082 if ((ioflg & IO_NODELOCKED) == 0) { 2083 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0) 2084 return (error); 2085 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 2086 } 2087 2088 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held"); 2089 2090 /* authorize attribute removal as kernel */ 2091 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td); 2092 if (error == EOPNOTSUPP) 2093 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL, 2094 NULL, td); 2095 2096 if ((ioflg & IO_NODELOCKED) == 0) { 2097 vn_finished_write(mp); 2098 VOP_UNLOCK(vp, 0); 2099 } 2100 2101 return (error); 2102 } 2103 2104 static int 2105 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags, 2106 struct vnode **rvp) 2107 { 2108 2109 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp)); 2110 } 2111 2112 int 2113 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp) 2114 { 2115 2116 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino, 2117 lkflags, rvp)); 2118 } 2119 2120 int 2121 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg, 2122 int lkflags, struct vnode **rvp) 2123 { 2124 struct mount *mp; 2125 int ltype, error; 2126 2127 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get"); 2128 mp = vp->v_mount; 2129 ltype = VOP_ISLOCKED(vp); 2130 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED, 2131 ("vn_vget_ino: vp not locked")); 2132 error = vfs_busy(mp, MBF_NOWAIT); 2133 if (error != 0) { 2134 vfs_ref(mp); 2135 VOP_UNLOCK(vp, 0); 2136 error = vfs_busy(mp, 0); 2137 vn_lock(vp, ltype | LK_RETRY); 2138 vfs_rel(mp); 2139 if (error != 0) 2140 return (ENOENT); 2141 if (vp->v_iflag & VI_DOOMED) { 2142 vfs_unbusy(mp); 2143 return (ENOENT); 2144 } 2145 } 2146 VOP_UNLOCK(vp, 0); 2147 error = alloc(mp, alloc_arg, lkflags, rvp); 2148 vfs_unbusy(mp); 2149 if (*rvp != vp) 2150 vn_lock(vp, ltype | LK_RETRY); 2151 if (vp->v_iflag & VI_DOOMED) { 2152 if (error == 0) { 2153 if (*rvp == vp) 2154 vunref(vp); 2155 else 2156 vput(*rvp); 2157 } 2158 error = ENOENT; 2159 } 2160 return (error); 2161 } 2162 2163 int 2164 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio, 2165 struct thread *td) 2166 { 2167 2168 if (vp->v_type != VREG || td == NULL) 2169 return (0); 2170 if ((uoff_t)uio->uio_offset + uio->uio_resid > 2171 lim_cur(td, RLIMIT_FSIZE)) { 2172 PROC_LOCK(td->td_proc); 2173 kern_psignal(td->td_proc, SIGXFSZ); 2174 PROC_UNLOCK(td->td_proc); 2175 return (EFBIG); 2176 } 2177 return (0); 2178 } 2179 2180 int 2181 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, 2182 struct thread *td) 2183 { 2184 struct vnode *vp; 2185 2186 vp = fp->f_vnode; 2187 #ifdef AUDIT 2188 vn_lock(vp, LK_SHARED | LK_RETRY); 2189 AUDIT_ARG_VNODE1(vp); 2190 VOP_UNLOCK(vp, 0); 2191 #endif 2192 return (setfmode(td, active_cred, vp, mode)); 2193 } 2194 2195 int 2196 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred, 2197 struct thread *td) 2198 { 2199 struct vnode *vp; 2200 2201 vp = fp->f_vnode; 2202 #ifdef AUDIT 2203 vn_lock(vp, LK_SHARED | LK_RETRY); 2204 AUDIT_ARG_VNODE1(vp); 2205 VOP_UNLOCK(vp, 0); 2206 #endif 2207 return (setfown(td, active_cred, vp, uid, gid)); 2208 } 2209 2210 void 2211 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end) 2212 { 2213 vm_object_t object; 2214 2215 if ((object = vp->v_object) == NULL) 2216 return; 2217 VM_OBJECT_WLOCK(object); 2218 vm_object_page_remove(object, start, end, 0); 2219 VM_OBJECT_WUNLOCK(object); 2220 } 2221 2222 int 2223 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred) 2224 { 2225 struct vattr va; 2226 daddr_t bn, bnp; 2227 uint64_t bsize; 2228 off_t noff; 2229 int error; 2230 2231 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA, 2232 ("Wrong command %lu", cmd)); 2233 2234 if (vn_lock(vp, LK_SHARED) != 0) 2235 return (EBADF); 2236 if (vp->v_type != VREG) { 2237 error = ENOTTY; 2238 goto unlock; 2239 } 2240 error = VOP_GETATTR(vp, &va, cred); 2241 if (error != 0) 2242 goto unlock; 2243 noff = *off; 2244 if (noff >= va.va_size) { 2245 error = ENXIO; 2246 goto unlock; 2247 } 2248 bsize = vp->v_mount->mnt_stat.f_iosize; 2249 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize) { 2250 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL); 2251 if (error == EOPNOTSUPP) { 2252 error = ENOTTY; 2253 goto unlock; 2254 } 2255 if ((bnp == -1 && cmd == FIOSEEKHOLE) || 2256 (bnp != -1 && cmd == FIOSEEKDATA)) { 2257 noff = bn * bsize; 2258 if (noff < *off) 2259 noff = *off; 2260 goto unlock; 2261 } 2262 } 2263 if (noff > va.va_size) 2264 noff = va.va_size; 2265 /* noff == va.va_size. There is an implicit hole at the end of file. */ 2266 if (cmd == FIOSEEKDATA) 2267 error = ENXIO; 2268 unlock: 2269 VOP_UNLOCK(vp, 0); 2270 if (error == 0) 2271 *off = noff; 2272 return (error); 2273 } 2274 2275 int 2276 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td) 2277 { 2278 struct ucred *cred; 2279 struct vnode *vp; 2280 struct vattr vattr; 2281 off_t foffset, size; 2282 int error, noneg; 2283 2284 cred = td->td_ucred; 2285 vp = fp->f_vnode; 2286 foffset = foffset_lock(fp, 0); 2287 noneg = (vp->v_type != VCHR); 2288 error = 0; 2289 switch (whence) { 2290 case L_INCR: 2291 if (noneg && 2292 (foffset < 0 || 2293 (offset > 0 && foffset > OFF_MAX - offset))) { 2294 error = EOVERFLOW; 2295 break; 2296 } 2297 offset += foffset; 2298 break; 2299 case L_XTND: 2300 vn_lock(vp, LK_SHARED | LK_RETRY); 2301 error = VOP_GETATTR(vp, &vattr, cred); 2302 VOP_UNLOCK(vp, 0); 2303 if (error) 2304 break; 2305 2306 /* 2307 * If the file references a disk device, then fetch 2308 * the media size and use that to determine the ending 2309 * offset. 2310 */ 2311 if (vattr.va_size == 0 && vp->v_type == VCHR && 2312 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0) 2313 vattr.va_size = size; 2314 if (noneg && 2315 (vattr.va_size > OFF_MAX || 2316 (offset > 0 && vattr.va_size > OFF_MAX - offset))) { 2317 error = EOVERFLOW; 2318 break; 2319 } 2320 offset += vattr.va_size; 2321 break; 2322 case L_SET: 2323 break; 2324 case SEEK_DATA: 2325 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td); 2326 break; 2327 case SEEK_HOLE: 2328 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td); 2329 break; 2330 default: 2331 error = EINVAL; 2332 } 2333 if (error == 0 && noneg && offset < 0) 2334 error = EINVAL; 2335 if (error != 0) 2336 goto drop; 2337 VFS_KNOTE_UNLOCKED(vp, 0); 2338 td->td_uretoff.tdu_off = offset; 2339 drop: 2340 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0); 2341 return (error); 2342 } 2343 2344 int 2345 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred, 2346 struct thread *td) 2347 { 2348 int error; 2349 2350 /* 2351 * Grant permission if the caller is the owner of the file, or 2352 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on 2353 * on the file. If the time pointer is null, then write 2354 * permission on the file is also sufficient. 2355 * 2356 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes: 2357 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES 2358 * will be allowed to set the times [..] to the current 2359 * server time. 2360 */ 2361 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td); 2362 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0) 2363 error = VOP_ACCESS(vp, VWRITE, cred, td); 2364 return (error); 2365 } 2366 2367 int 2368 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2369 { 2370 struct vnode *vp; 2371 int error; 2372 2373 if (fp->f_type == DTYPE_FIFO) 2374 kif->kf_type = KF_TYPE_FIFO; 2375 else 2376 kif->kf_type = KF_TYPE_VNODE; 2377 vp = fp->f_vnode; 2378 vref(vp); 2379 FILEDESC_SUNLOCK(fdp); 2380 error = vn_fill_kinfo_vnode(vp, kif); 2381 vrele(vp); 2382 FILEDESC_SLOCK(fdp); 2383 return (error); 2384 } 2385 2386 static inline void 2387 vn_fill_junk(struct kinfo_file *kif) 2388 { 2389 size_t len, olen; 2390 2391 /* 2392 * Simulate vn_fullpath returning changing values for a given 2393 * vp during e.g. coredump. 2394 */ 2395 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1; 2396 olen = strlen(kif->kf_path); 2397 if (len < olen) 2398 strcpy(&kif->kf_path[len - 1], "$"); 2399 else 2400 for (; olen < len; olen++) 2401 strcpy(&kif->kf_path[olen], "A"); 2402 } 2403 2404 int 2405 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif) 2406 { 2407 struct vattr va; 2408 char *fullpath, *freepath; 2409 int error; 2410 2411 kif->kf_vnode_type = vntype_to_kinfo(vp->v_type); 2412 freepath = NULL; 2413 fullpath = "-"; 2414 error = vn_fullpath(curthread, vp, &fullpath, &freepath); 2415 if (error == 0) { 2416 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path)); 2417 } 2418 if (freepath != NULL) 2419 free(freepath, M_TEMP); 2420 2421 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path, 2422 vn_fill_junk(kif); 2423 ); 2424 2425 /* 2426 * Retrieve vnode attributes. 2427 */ 2428 va.va_fsid = VNOVAL; 2429 va.va_rdev = NODEV; 2430 vn_lock(vp, LK_SHARED | LK_RETRY); 2431 error = VOP_GETATTR(vp, &va, curthread->td_ucred); 2432 VOP_UNLOCK(vp, 0); 2433 if (error != 0) 2434 return (error); 2435 if (va.va_fsid != VNOVAL) 2436 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid; 2437 else 2438 kif->kf_un.kf_file.kf_file_fsid = 2439 vp->v_mount->mnt_stat.f_fsid.val[0]; 2440 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid; 2441 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode); 2442 kif->kf_un.kf_file.kf_file_size = va.va_size; 2443 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev; 2444 return (0); 2445 } 2446 2447 int 2448 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size, 2449 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff, 2450 struct thread *td) 2451 { 2452 #ifdef HWPMC_HOOKS 2453 struct pmckern_map_in pkm; 2454 #endif 2455 struct mount *mp; 2456 struct vnode *vp; 2457 vm_object_t object; 2458 vm_prot_t maxprot; 2459 boolean_t writecounted; 2460 int error; 2461 2462 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \ 2463 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4) 2464 /* 2465 * POSIX shared-memory objects are defined to have 2466 * kernel persistence, and are not defined to support 2467 * read(2)/write(2) -- or even open(2). Thus, we can 2468 * use MAP_ASYNC to trade on-disk coherence for speed. 2469 * The shm_open(3) library routine turns on the FPOSIXSHM 2470 * flag to request this behavior. 2471 */ 2472 if ((fp->f_flag & FPOSIXSHM) != 0) 2473 flags |= MAP_NOSYNC; 2474 #endif 2475 vp = fp->f_vnode; 2476 2477 /* 2478 * Ensure that file and memory protections are 2479 * compatible. Note that we only worry about 2480 * writability if mapping is shared; in this case, 2481 * current and max prot are dictated by the open file. 2482 * XXX use the vnode instead? Problem is: what 2483 * credentials do we use for determination? What if 2484 * proc does a setuid? 2485 */ 2486 mp = vp->v_mount; 2487 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0) 2488 maxprot = VM_PROT_NONE; 2489 else 2490 maxprot = VM_PROT_EXECUTE; 2491 if ((fp->f_flag & FREAD) != 0) 2492 maxprot |= VM_PROT_READ; 2493 else if ((prot & VM_PROT_READ) != 0) 2494 return (EACCES); 2495 2496 /* 2497 * If we are sharing potential changes via MAP_SHARED and we 2498 * are trying to get write permission although we opened it 2499 * without asking for it, bail out. 2500 */ 2501 if ((flags & MAP_SHARED) != 0) { 2502 if ((fp->f_flag & FWRITE) != 0) 2503 maxprot |= VM_PROT_WRITE; 2504 else if ((prot & VM_PROT_WRITE) != 0) 2505 return (EACCES); 2506 } else { 2507 maxprot |= VM_PROT_WRITE; 2508 cap_maxprot |= VM_PROT_WRITE; 2509 } 2510 maxprot &= cap_maxprot; 2511 2512 writecounted = FALSE; 2513 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp, 2514 &foff, &object, &writecounted); 2515 if (error != 0) 2516 return (error); 2517 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object, 2518 foff, writecounted, td); 2519 if (error != 0) { 2520 /* 2521 * If this mapping was accounted for in the vnode's 2522 * writecount, then undo that now. 2523 */ 2524 if (writecounted) 2525 vnode_pager_release_writecount(object, 0, size); 2526 vm_object_deallocate(object); 2527 } 2528 #ifdef HWPMC_HOOKS 2529 /* Inform hwpmc(4) if an executable is being mapped. */ 2530 if (error == 0 && (prot & VM_PROT_EXECUTE) != 0) { 2531 pkm.pm_file = vp; 2532 pkm.pm_address = (uintptr_t) addr; 2533 PMC_CALL_HOOK(td, PMC_FN_MMAP, (void *) &pkm); 2534 } 2535 #endif 2536 return (error); 2537 } 2538