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