FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_vnops.c
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: releng/11.0/sys/kern/vfs_vnops.c 302345 2016-07-05 16:37:01Z rwatson $");
45
46 #include "opt_hwpmc_hooks.h"
47
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/disk.h>
51 #include <sys/fail.h>
52 #include <sys/fcntl.h>
53 #include <sys/file.h>
54 #include <sys/kdb.h>
55 #include <sys/stat.h>
56 #include <sys/priv.h>
57 #include <sys/proc.h>
58 #include <sys/limits.h>
59 #include <sys/lock.h>
60 #include <sys/mman.h>
61 #include <sys/mount.h>
62 #include <sys/mutex.h>
63 #include <sys/namei.h>
64 #include <sys/vnode.h>
65 #include <sys/bio.h>
66 #include <sys/buf.h>
67 #include <sys/filio.h>
68 #include <sys/resourcevar.h>
69 #include <sys/rwlock.h>
70 #include <sys/sx.h>
71 #include <sys/sysctl.h>
72 #include <sys/ttycom.h>
73 #include <sys/conf.h>
74 #include <sys/syslog.h>
75 #include <sys/unistd.h>
76 #include <sys/user.h>
77
78 #include <security/audit/audit.h>
79 #include <security/mac/mac_framework.h>
80
81 #include <vm/vm.h>
82 #include <vm/vm_extern.h>
83 #include <vm/pmap.h>
84 #include <vm/vm_map.h>
85 #include <vm/vm_object.h>
86 #include <vm/vm_page.h>
87 #include <vm/vnode_pager.h>
88
89 #ifdef HWPMC_HOOKS
90 #include <sys/pmckern.h>
91 #endif
92
93 static fo_rdwr_t vn_read;
94 static fo_rdwr_t vn_write;
95 static fo_rdwr_t vn_io_fault;
96 static fo_truncate_t vn_truncate;
97 static fo_ioctl_t vn_ioctl;
98 static fo_poll_t vn_poll;
99 static fo_kqfilter_t vn_kqfilter;
100 static fo_stat_t vn_statfile;
101 static fo_close_t vn_closefile;
102 static fo_mmap_t vn_mmap;
103
104 struct fileops vnops = {
105 .fo_read = vn_io_fault,
106 .fo_write = vn_io_fault,
107 .fo_truncate = vn_truncate,
108 .fo_ioctl = vn_ioctl,
109 .fo_poll = vn_poll,
110 .fo_kqfilter = vn_kqfilter,
111 .fo_stat = vn_statfile,
112 .fo_close = vn_closefile,
113 .fo_chmod = vn_chmod,
114 .fo_chown = vn_chown,
115 .fo_sendfile = vn_sendfile,
116 .fo_seek = vn_seek,
117 .fo_fill_kinfo = vn_fill_kinfo,
118 .fo_mmap = vn_mmap,
119 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
120 };
121
122 static const int io_hold_cnt = 16;
123 static int vn_io_fault_enable = 1;
124 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RW,
125 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance");
126 static int vn_io_fault_prefault = 0;
127 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RW,
128 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting");
129 static u_long vn_io_faults_cnt;
130 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD,
131 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers");
132
133 /*
134 * Returns true if vn_io_fault mode of handling the i/o request should
135 * be used.
136 */
137 static bool
138 do_vn_io_fault(struct vnode *vp, struct uio *uio)
139 {
140 struct mount *mp;
141
142 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG &&
143 (mp = vp->v_mount) != NULL &&
144 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable);
145 }
146
147 /*
148 * Structure used to pass arguments to vn_io_fault1(), to do either
149 * file- or vnode-based I/O calls.
150 */
151 struct vn_io_fault_args {
152 enum {
153 VN_IO_FAULT_FOP,
154 VN_IO_FAULT_VOP
155 } kind;
156 struct ucred *cred;
157 int flags;
158 union {
159 struct fop_args_tag {
160 struct file *fp;
161 fo_rdwr_t *doio;
162 } fop_args;
163 struct vop_args_tag {
164 struct vnode *vp;
165 } vop_args;
166 } args;
167 };
168
169 static int vn_io_fault1(struct vnode *vp, struct uio *uio,
170 struct vn_io_fault_args *args, struct thread *td);
171
172 int
173 vn_open(ndp, flagp, cmode, fp)
174 struct nameidata *ndp;
175 int *flagp, cmode;
176 struct file *fp;
177 {
178 struct thread *td = ndp->ni_cnd.cn_thread;
179
180 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp));
181 }
182
183 /*
184 * Common code for vnode open operations via a name lookup.
185 * Lookup the vnode and invoke VOP_CREATE if needed.
186 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine.
187 *
188 * Note that this does NOT free nameidata for the successful case,
189 * due to the NDINIT being done elsewhere.
190 */
191 int
192 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags,
193 struct ucred *cred, struct file *fp)
194 {
195 struct vnode *vp;
196 struct mount *mp;
197 struct thread *td = ndp->ni_cnd.cn_thread;
198 struct vattr vat;
199 struct vattr *vap = &vat;
200 int fmode, error;
201
202 restart:
203 fmode = *flagp;
204 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT |
205 O_EXCL | O_DIRECTORY))
206 return (EINVAL);
207 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) {
208 ndp->ni_cnd.cn_nameiop = CREATE;
209 /*
210 * Set NOCACHE to avoid flushing the cache when
211 * rolling in many files at once.
212 */
213 ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF | NOCACHE;
214 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
215 ndp->ni_cnd.cn_flags |= FOLLOW;
216 if (!(vn_open_flags & VN_OPEN_NOAUDIT))
217 ndp->ni_cnd.cn_flags |= AUDITVNODE1;
218 if (vn_open_flags & VN_OPEN_NOCAPCHECK)
219 ndp->ni_cnd.cn_flags |= NOCAPCHECK;
220 bwillwrite();
221 if ((error = namei(ndp)) != 0)
222 return (error);
223 if (ndp->ni_vp == NULL) {
224 VATTR_NULL(vap);
225 vap->va_type = VREG;
226 vap->va_mode = cmode;
227 if (fmode & O_EXCL)
228 vap->va_vaflags |= VA_EXCLUSIVE;
229 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) {
230 NDFREE(ndp, NDF_ONLY_PNBUF);
231 vput(ndp->ni_dvp);
232 if ((error = vn_start_write(NULL, &mp,
233 V_XSLEEP | PCATCH)) != 0)
234 return (error);
235 goto restart;
236 }
237 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0)
238 ndp->ni_cnd.cn_flags |= MAKEENTRY;
239 #ifdef MAC
240 error = mac_vnode_check_create(cred, ndp->ni_dvp,
241 &ndp->ni_cnd, vap);
242 if (error == 0)
243 #endif
244 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
245 &ndp->ni_cnd, vap);
246 vput(ndp->ni_dvp);
247 vn_finished_write(mp);
248 if (error) {
249 NDFREE(ndp, NDF_ONLY_PNBUF);
250 return (error);
251 }
252 fmode &= ~O_TRUNC;
253 vp = ndp->ni_vp;
254 } else {
255 if (ndp->ni_dvp == ndp->ni_vp)
256 vrele(ndp->ni_dvp);
257 else
258 vput(ndp->ni_dvp);
259 ndp->ni_dvp = NULL;
260 vp = ndp->ni_vp;
261 if (fmode & O_EXCL) {
262 error = EEXIST;
263 goto bad;
264 }
265 fmode &= ~O_CREAT;
266 }
267 } else {
268 ndp->ni_cnd.cn_nameiop = LOOKUP;
269 ndp->ni_cnd.cn_flags = ISOPEN |
270 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF;
271 if (!(fmode & FWRITE))
272 ndp->ni_cnd.cn_flags |= LOCKSHARED;
273 if (!(vn_open_flags & VN_OPEN_NOAUDIT))
274 ndp->ni_cnd.cn_flags |= AUDITVNODE1;
275 if (vn_open_flags & VN_OPEN_NOCAPCHECK)
276 ndp->ni_cnd.cn_flags |= NOCAPCHECK;
277 if ((error = namei(ndp)) != 0)
278 return (error);
279 vp = ndp->ni_vp;
280 }
281 error = vn_open_vnode(vp, fmode, cred, td, fp);
282 if (error)
283 goto bad;
284 *flagp = fmode;
285 return (0);
286 bad:
287 NDFREE(ndp, NDF_ONLY_PNBUF);
288 vput(vp);
289 *flagp = fmode;
290 ndp->ni_vp = NULL;
291 return (error);
292 }
293
294 /*
295 * Common code for vnode open operations once a vnode is located.
296 * Check permissions, and call the VOP_OPEN routine.
297 */
298 int
299 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred,
300 struct thread *td, struct file *fp)
301 {
302 accmode_t accmode;
303 struct flock lf;
304 int error, lock_flags, type;
305
306 if (vp->v_type == VLNK)
307 return (EMLINK);
308 if (vp->v_type == VSOCK)
309 return (EOPNOTSUPP);
310 if (vp->v_type != VDIR && fmode & O_DIRECTORY)
311 return (ENOTDIR);
312 accmode = 0;
313 if (fmode & (FWRITE | O_TRUNC)) {
314 if (vp->v_type == VDIR)
315 return (EISDIR);
316 accmode |= VWRITE;
317 }
318 if (fmode & FREAD)
319 accmode |= VREAD;
320 if (fmode & FEXEC)
321 accmode |= VEXEC;
322 if ((fmode & O_APPEND) && (fmode & FWRITE))
323 accmode |= VAPPEND;
324 #ifdef MAC
325 if (fmode & O_CREAT)
326 accmode |= VCREAT;
327 if (fmode & O_VERIFY)
328 accmode |= VVERIFY;
329 error = mac_vnode_check_open(cred, vp, accmode);
330 if (error)
331 return (error);
332
333 accmode &= ~(VCREAT | VVERIFY);
334 #endif
335 if ((fmode & O_CREAT) == 0) {
336 if (accmode & VWRITE) {
337 error = vn_writechk(vp);
338 if (error)
339 return (error);
340 }
341 if (accmode) {
342 error = VOP_ACCESS(vp, accmode, cred, td);
343 if (error)
344 return (error);
345 }
346 }
347 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
348 vn_lock(vp, LK_UPGRADE | LK_RETRY);
349 if ((error = VOP_OPEN(vp, fmode, cred, td, fp)) != 0)
350 return (error);
351
352 if (fmode & (O_EXLOCK | O_SHLOCK)) {
353 KASSERT(fp != NULL, ("open with flock requires fp"));
354 lock_flags = VOP_ISLOCKED(vp);
355 VOP_UNLOCK(vp, 0);
356 lf.l_whence = SEEK_SET;
357 lf.l_start = 0;
358 lf.l_len = 0;
359 if (fmode & O_EXLOCK)
360 lf.l_type = F_WRLCK;
361 else
362 lf.l_type = F_RDLCK;
363 type = F_FLOCK;
364 if ((fmode & FNONBLOCK) == 0)
365 type |= F_WAIT;
366 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type);
367 if (error == 0)
368 fp->f_flag |= FHASLOCK;
369 vn_lock(vp, lock_flags | LK_RETRY);
370 if (error == 0 && vp->v_iflag & VI_DOOMED)
371 error = ENOENT;
372
373 /*
374 * Another thread might have used this vnode as an
375 * executable while the vnode lock was dropped.
376 * Ensure the vnode is still able to be opened for
377 * writing after the lock has been obtained.
378 */
379 if (error == 0 && accmode & VWRITE)
380 error = vn_writechk(vp);
381
382 if (error != 0) {
383 fp->f_flag |= FOPENFAILED;
384 fp->f_vnode = vp;
385 if (fp->f_ops == &badfileops) {
386 fp->f_type = DTYPE_VNODE;
387 fp->f_ops = &vnops;
388 }
389 vref(vp);
390 }
391 }
392 if (error == 0 && fmode & FWRITE) {
393 VOP_ADD_WRITECOUNT(vp, 1);
394 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
395 __func__, vp, vp->v_writecount);
396 }
397 ASSERT_VOP_LOCKED(vp, "vn_open_vnode");
398 return (error);
399 }
400
401 /*
402 * Check for write permissions on the specified vnode.
403 * Prototype text segments cannot be written.
404 */
405 int
406 vn_writechk(vp)
407 register struct vnode *vp;
408 {
409
410 ASSERT_VOP_LOCKED(vp, "vn_writechk");
411 /*
412 * If there's shared text associated with
413 * the vnode, try to free it up once. If
414 * we fail, we can't allow writing.
415 */
416 if (VOP_IS_TEXT(vp))
417 return (ETXTBSY);
418
419 return (0);
420 }
421
422 /*
423 * Vnode close call
424 */
425 int
426 vn_close(vp, flags, file_cred, td)
427 register struct vnode *vp;
428 int flags;
429 struct ucred *file_cred;
430 struct thread *td;
431 {
432 struct mount *mp;
433 int error, lock_flags;
434
435 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 &&
436 MNT_EXTENDED_SHARED(vp->v_mount))
437 lock_flags = LK_SHARED;
438 else
439 lock_flags = LK_EXCLUSIVE;
440
441 vn_start_write(vp, &mp, V_WAIT);
442 vn_lock(vp, lock_flags | LK_RETRY);
443 AUDIT_ARG_VNODE1(vp);
444 if ((flags & (FWRITE | FOPENFAILED)) == FWRITE) {
445 VNASSERT(vp->v_writecount > 0, vp,
446 ("vn_close: negative writecount"));
447 VOP_ADD_WRITECOUNT(vp, -1);
448 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
449 __func__, vp, vp->v_writecount);
450 }
451 error = VOP_CLOSE(vp, flags, file_cred, td);
452 vput(vp);
453 vn_finished_write(mp);
454 return (error);
455 }
456
457 /*
458 * Heuristic to detect sequential operation.
459 */
460 static int
461 sequential_heuristic(struct uio *uio, struct file *fp)
462 {
463
464 ASSERT_VOP_LOCKED(fp->f_vnode, __func__);
465 if (fp->f_flag & FRDAHEAD)
466 return (fp->f_seqcount << IO_SEQSHIFT);
467
468 /*
469 * Offset 0 is handled specially. open() sets f_seqcount to 1 so
470 * that the first I/O is normally considered to be slightly
471 * sequential. Seeking to offset 0 doesn't change sequentiality
472 * unless previous seeks have reduced f_seqcount to 0, in which
473 * case offset 0 is not special.
474 */
475 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
476 uio->uio_offset == fp->f_nextoff) {
477 /*
478 * f_seqcount is in units of fixed-size blocks so that it
479 * depends mainly on the amount of sequential I/O and not
480 * much on the number of sequential I/O's. The fixed size
481 * of 16384 is hard-coded here since it is (not quite) just
482 * a magic size that works well here. This size is more
483 * closely related to the best I/O size for real disks than
484 * to any block size used by software.
485 */
486 fp->f_seqcount += howmany(uio->uio_resid, 16384);
487 if (fp->f_seqcount > IO_SEQMAX)
488 fp->f_seqcount = IO_SEQMAX;
489 return (fp->f_seqcount << IO_SEQSHIFT);
490 }
491
492 /* Not sequential. Quickly draw-down sequentiality. */
493 if (fp->f_seqcount > 1)
494 fp->f_seqcount = 1;
495 else
496 fp->f_seqcount = 0;
497 return (0);
498 }
499
500 /*
501 * Package up an I/O request on a vnode into a uio and do it.
502 */
503 int
504 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset,
505 enum uio_seg segflg, int ioflg, struct ucred *active_cred,
506 struct ucred *file_cred, ssize_t *aresid, struct thread *td)
507 {
508 struct uio auio;
509 struct iovec aiov;
510 struct mount *mp;
511 struct ucred *cred;
512 void *rl_cookie;
513 struct vn_io_fault_args args;
514 int error, lock_flags;
515
516 auio.uio_iov = &aiov;
517 auio.uio_iovcnt = 1;
518 aiov.iov_base = base;
519 aiov.iov_len = len;
520 auio.uio_resid = len;
521 auio.uio_offset = offset;
522 auio.uio_segflg = segflg;
523 auio.uio_rw = rw;
524 auio.uio_td = td;
525 error = 0;
526
527 if ((ioflg & IO_NODELOCKED) == 0) {
528 if ((ioflg & IO_RANGELOCKED) == 0) {
529 if (rw == UIO_READ) {
530 rl_cookie = vn_rangelock_rlock(vp, offset,
531 offset + len);
532 } else {
533 rl_cookie = vn_rangelock_wlock(vp, offset,
534 offset + len);
535 }
536 } else
537 rl_cookie = NULL;
538 mp = NULL;
539 if (rw == UIO_WRITE) {
540 if (vp->v_type != VCHR &&
541 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
542 != 0)
543 goto out;
544 if (MNT_SHARED_WRITES(mp) ||
545 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount)))
546 lock_flags = LK_SHARED;
547 else
548 lock_flags = LK_EXCLUSIVE;
549 } else
550 lock_flags = LK_SHARED;
551 vn_lock(vp, lock_flags | LK_RETRY);
552 } else
553 rl_cookie = NULL;
554
555 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
556 #ifdef MAC
557 if ((ioflg & IO_NOMACCHECK) == 0) {
558 if (rw == UIO_READ)
559 error = mac_vnode_check_read(active_cred, file_cred,
560 vp);
561 else
562 error = mac_vnode_check_write(active_cred, file_cred,
563 vp);
564 }
565 #endif
566 if (error == 0) {
567 if (file_cred != NULL)
568 cred = file_cred;
569 else
570 cred = active_cred;
571 if (do_vn_io_fault(vp, &auio)) {
572 args.kind = VN_IO_FAULT_VOP;
573 args.cred = cred;
574 args.flags = ioflg;
575 args.args.vop_args.vp = vp;
576 error = vn_io_fault1(vp, &auio, &args, td);
577 } else if (rw == UIO_READ) {
578 error = VOP_READ(vp, &auio, ioflg, cred);
579 } else /* if (rw == UIO_WRITE) */ {
580 error = VOP_WRITE(vp, &auio, ioflg, cred);
581 }
582 }
583 if (aresid)
584 *aresid = auio.uio_resid;
585 else
586 if (auio.uio_resid && error == 0)
587 error = EIO;
588 if ((ioflg & IO_NODELOCKED) == 0) {
589 VOP_UNLOCK(vp, 0);
590 if (mp != NULL)
591 vn_finished_write(mp);
592 }
593 out:
594 if (rl_cookie != NULL)
595 vn_rangelock_unlock(vp, rl_cookie);
596 return (error);
597 }
598
599 /*
600 * Package up an I/O request on a vnode into a uio and do it. The I/O
601 * request is split up into smaller chunks and we try to avoid saturating
602 * the buffer cache while potentially holding a vnode locked, so we
603 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield()
604 * to give other processes a chance to lock the vnode (either other processes
605 * core'ing the same binary, or unrelated processes scanning the directory).
606 */
607 int
608 vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred,
609 file_cred, aresid, td)
610 enum uio_rw rw;
611 struct vnode *vp;
612 void *base;
613 size_t len;
614 off_t offset;
615 enum uio_seg segflg;
616 int ioflg;
617 struct ucred *active_cred;
618 struct ucred *file_cred;
619 size_t *aresid;
620 struct thread *td;
621 {
622 int error = 0;
623 ssize_t iaresid;
624
625 do {
626 int chunk;
627
628 /*
629 * Force `offset' to a multiple of MAXBSIZE except possibly
630 * for the first chunk, so that filesystems only need to
631 * write full blocks except possibly for the first and last
632 * chunks.
633 */
634 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE;
635
636 if (chunk > len)
637 chunk = len;
638 if (rw != UIO_READ && vp->v_type == VREG)
639 bwillwrite();
640 iaresid = 0;
641 error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
642 ioflg, active_cred, file_cred, &iaresid, td);
643 len -= chunk; /* aresid calc already includes length */
644 if (error)
645 break;
646 offset += chunk;
647 base = (char *)base + chunk;
648 kern_yield(PRI_USER);
649 } while (len);
650 if (aresid)
651 *aresid = len + iaresid;
652 return (error);
653 }
654
655 off_t
656 foffset_lock(struct file *fp, int flags)
657 {
658 struct mtx *mtxp;
659 off_t res;
660
661 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
662
663 #if OFF_MAX <= LONG_MAX
664 /*
665 * Caller only wants the current f_offset value. Assume that
666 * the long and shorter integer types reads are atomic.
667 */
668 if ((flags & FOF_NOLOCK) != 0)
669 return (fp->f_offset);
670 #endif
671
672 /*
673 * According to McKusick the vn lock was protecting f_offset here.
674 * It is now protected by the FOFFSET_LOCKED flag.
675 */
676 mtxp = mtx_pool_find(mtxpool_sleep, fp);
677 mtx_lock(mtxp);
678 if ((flags & FOF_NOLOCK) == 0) {
679 while (fp->f_vnread_flags & FOFFSET_LOCKED) {
680 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING;
681 msleep(&fp->f_vnread_flags, mtxp, PUSER -1,
682 "vofflock", 0);
683 }
684 fp->f_vnread_flags |= FOFFSET_LOCKED;
685 }
686 res = fp->f_offset;
687 mtx_unlock(mtxp);
688 return (res);
689 }
690
691 void
692 foffset_unlock(struct file *fp, off_t val, int flags)
693 {
694 struct mtx *mtxp;
695
696 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
697
698 #if OFF_MAX <= LONG_MAX
699 if ((flags & FOF_NOLOCK) != 0) {
700 if ((flags & FOF_NOUPDATE) == 0)
701 fp->f_offset = val;
702 if ((flags & FOF_NEXTOFF) != 0)
703 fp->f_nextoff = val;
704 return;
705 }
706 #endif
707
708 mtxp = mtx_pool_find(mtxpool_sleep, fp);
709 mtx_lock(mtxp);
710 if ((flags & FOF_NOUPDATE) == 0)
711 fp->f_offset = val;
712 if ((flags & FOF_NEXTOFF) != 0)
713 fp->f_nextoff = val;
714 if ((flags & FOF_NOLOCK) == 0) {
715 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0,
716 ("Lost FOFFSET_LOCKED"));
717 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING)
718 wakeup(&fp->f_vnread_flags);
719 fp->f_vnread_flags = 0;
720 }
721 mtx_unlock(mtxp);
722 }
723
724 void
725 foffset_lock_uio(struct file *fp, struct uio *uio, int flags)
726 {
727
728 if ((flags & FOF_OFFSET) == 0)
729 uio->uio_offset = foffset_lock(fp, flags);
730 }
731
732 void
733 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags)
734 {
735
736 if ((flags & FOF_OFFSET) == 0)
737 foffset_unlock(fp, uio->uio_offset, flags);
738 }
739
740 static int
741 get_advice(struct file *fp, struct uio *uio)
742 {
743 struct mtx *mtxp;
744 int ret;
745
746 ret = POSIX_FADV_NORMAL;
747 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG)
748 return (ret);
749
750 mtxp = mtx_pool_find(mtxpool_sleep, fp);
751 mtx_lock(mtxp);
752 if (fp->f_advice != NULL &&
753 uio->uio_offset >= fp->f_advice->fa_start &&
754 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end)
755 ret = fp->f_advice->fa_advice;
756 mtx_unlock(mtxp);
757 return (ret);
758 }
759
760 /*
761 * File table vnode read routine.
762 */
763 static int
764 vn_read(fp, uio, active_cred, flags, td)
765 struct file *fp;
766 struct uio *uio;
767 struct ucred *active_cred;
768 int flags;
769 struct thread *td;
770 {
771 struct vnode *vp;
772 off_t orig_offset;
773 int error, ioflag;
774 int advice;
775
776 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
777 uio->uio_td, td));
778 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
779 vp = fp->f_vnode;
780 ioflag = 0;
781 if (fp->f_flag & FNONBLOCK)
782 ioflag |= IO_NDELAY;
783 if (fp->f_flag & O_DIRECT)
784 ioflag |= IO_DIRECT;
785 advice = get_advice(fp, uio);
786 vn_lock(vp, LK_SHARED | LK_RETRY);
787
788 switch (advice) {
789 case POSIX_FADV_NORMAL:
790 case POSIX_FADV_SEQUENTIAL:
791 case POSIX_FADV_NOREUSE:
792 ioflag |= sequential_heuristic(uio, fp);
793 break;
794 case POSIX_FADV_RANDOM:
795 /* Disable read-ahead for random I/O. */
796 break;
797 }
798 orig_offset = uio->uio_offset;
799
800 #ifdef MAC
801 error = mac_vnode_check_read(active_cred, fp->f_cred, vp);
802 if (error == 0)
803 #endif
804 error = VOP_READ(vp, uio, ioflag, fp->f_cred);
805 fp->f_nextoff = uio->uio_offset;
806 VOP_UNLOCK(vp, 0);
807 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
808 orig_offset != uio->uio_offset)
809 /*
810 * Use POSIX_FADV_DONTNEED to flush pages and buffers
811 * for the backing file after a POSIX_FADV_NOREUSE
812 * read(2).
813 */
814 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
815 POSIX_FADV_DONTNEED);
816 return (error);
817 }
818
819 /*
820 * File table vnode write routine.
821 */
822 static int
823 vn_write(fp, uio, active_cred, flags, td)
824 struct file *fp;
825 struct uio *uio;
826 struct ucred *active_cred;
827 int flags;
828 struct thread *td;
829 {
830 struct vnode *vp;
831 struct mount *mp;
832 off_t orig_offset;
833 int error, ioflag, lock_flags;
834 int advice;
835
836 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
837 uio->uio_td, td));
838 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
839 vp = fp->f_vnode;
840 if (vp->v_type == VREG)
841 bwillwrite();
842 ioflag = IO_UNIT;
843 if (vp->v_type == VREG && (fp->f_flag & O_APPEND))
844 ioflag |= IO_APPEND;
845 if (fp->f_flag & FNONBLOCK)
846 ioflag |= IO_NDELAY;
847 if (fp->f_flag & O_DIRECT)
848 ioflag |= IO_DIRECT;
849 if ((fp->f_flag & O_FSYNC) ||
850 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS)))
851 ioflag |= IO_SYNC;
852 mp = NULL;
853 if (vp->v_type != VCHR &&
854 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
855 goto unlock;
856
857 advice = get_advice(fp, uio);
858
859 if (MNT_SHARED_WRITES(mp) ||
860 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) {
861 lock_flags = LK_SHARED;
862 } else {
863 lock_flags = LK_EXCLUSIVE;
864 }
865
866 vn_lock(vp, lock_flags | LK_RETRY);
867 switch (advice) {
868 case POSIX_FADV_NORMAL:
869 case POSIX_FADV_SEQUENTIAL:
870 case POSIX_FADV_NOREUSE:
871 ioflag |= sequential_heuristic(uio, fp);
872 break;
873 case POSIX_FADV_RANDOM:
874 /* XXX: Is this correct? */
875 break;
876 }
877 orig_offset = uio->uio_offset;
878
879 #ifdef MAC
880 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
881 if (error == 0)
882 #endif
883 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred);
884 fp->f_nextoff = uio->uio_offset;
885 VOP_UNLOCK(vp, 0);
886 if (vp->v_type != VCHR)
887 vn_finished_write(mp);
888 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
889 orig_offset != uio->uio_offset)
890 /*
891 * Use POSIX_FADV_DONTNEED to flush pages and buffers
892 * for the backing file after a POSIX_FADV_NOREUSE
893 * write(2).
894 */
895 error = VOP_ADVISE(vp, orig_offset, uio->uio_offset - 1,
896 POSIX_FADV_DONTNEED);
897 unlock:
898 return (error);
899 }
900
901 /*
902 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to
903 * prevent the following deadlock:
904 *
905 * Assume that the thread A reads from the vnode vp1 into userspace
906 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is
907 * currently not resident, then system ends up with the call chain
908 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] ->
909 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2)
910 * which establishes lock order vp1->vn_lock, then vp2->vn_lock.
911 * If, at the same time, thread B reads from vnode vp2 into buffer buf2
912 * backed by the pages of vnode vp1, and some page in buf2 is not
913 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock.
914 *
915 * To prevent the lock order reversal and deadlock, vn_io_fault() does
916 * not allow page faults to happen during VOP_READ() or VOP_WRITE().
917 * Instead, it first tries to do the whole range i/o with pagefaults
918 * disabled. If all pages in the i/o buffer are resident and mapped,
919 * VOP will succeed (ignoring the genuine filesystem errors).
920 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do
921 * i/o in chunks, with all pages in the chunk prefaulted and held
922 * using vm_fault_quick_hold_pages().
923 *
924 * Filesystems using this deadlock avoidance scheme should use the
925 * array of the held pages from uio, saved in the curthread->td_ma,
926 * instead of doing uiomove(). A helper function
927 * vn_io_fault_uiomove() converts uiomove request into
928 * uiomove_fromphys() over td_ma array.
929 *
930 * Since vnode locks do not cover the whole i/o anymore, rangelocks
931 * make the current i/o request atomic with respect to other i/os and
932 * truncations.
933 */
934
935 /*
936 * Decode vn_io_fault_args and perform the corresponding i/o.
937 */
938 static int
939 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio,
940 struct thread *td)
941 {
942
943 switch (args->kind) {
944 case VN_IO_FAULT_FOP:
945 return ((args->args.fop_args.doio)(args->args.fop_args.fp,
946 uio, args->cred, args->flags, td));
947 case VN_IO_FAULT_VOP:
948 if (uio->uio_rw == UIO_READ) {
949 return (VOP_READ(args->args.vop_args.vp, uio,
950 args->flags, args->cred));
951 } else if (uio->uio_rw == UIO_WRITE) {
952 return (VOP_WRITE(args->args.vop_args.vp, uio,
953 args->flags, args->cred));
954 }
955 break;
956 }
957 panic("vn_io_fault_doio: unknown kind of io %d %d", args->kind,
958 uio->uio_rw);
959 }
960
961 static int
962 vn_io_fault_touch(char *base, const struct uio *uio)
963 {
964 int r;
965
966 r = fubyte(base);
967 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1))
968 return (EFAULT);
969 return (0);
970 }
971
972 static int
973 vn_io_fault_prefault_user(const struct uio *uio)
974 {
975 char *base;
976 const struct iovec *iov;
977 size_t len;
978 ssize_t resid;
979 int error, i;
980
981 KASSERT(uio->uio_segflg == UIO_USERSPACE,
982 ("vn_io_fault_prefault userspace"));
983
984 error = i = 0;
985 iov = uio->uio_iov;
986 resid = uio->uio_resid;
987 base = iov->iov_base;
988 len = iov->iov_len;
989 while (resid > 0) {
990 error = vn_io_fault_touch(base, uio);
991 if (error != 0)
992 break;
993 if (len < PAGE_SIZE) {
994 if (len != 0) {
995 error = vn_io_fault_touch(base + len - 1, uio);
996 if (error != 0)
997 break;
998 resid -= len;
999 }
1000 if (++i >= uio->uio_iovcnt)
1001 break;
1002 iov = uio->uio_iov + i;
1003 base = iov->iov_base;
1004 len = iov->iov_len;
1005 } else {
1006 len -= PAGE_SIZE;
1007 base += PAGE_SIZE;
1008 resid -= PAGE_SIZE;
1009 }
1010 }
1011 return (error);
1012 }
1013
1014 /*
1015 * Common code for vn_io_fault(), agnostic to the kind of i/o request.
1016 * Uses vn_io_fault_doio() to make the call to an actual i/o function.
1017 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request
1018 * into args and call vn_io_fault1() to handle faults during the user
1019 * mode buffer accesses.
1020 */
1021 static int
1022 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args,
1023 struct thread *td)
1024 {
1025 vm_page_t ma[io_hold_cnt + 2];
1026 struct uio *uio_clone, short_uio;
1027 struct iovec short_iovec[1];
1028 vm_page_t *prev_td_ma;
1029 vm_prot_t prot;
1030 vm_offset_t addr, end;
1031 size_t len, resid;
1032 ssize_t adv;
1033 int error, cnt, save, saveheld, prev_td_ma_cnt;
1034
1035 if (vn_io_fault_prefault) {
1036 error = vn_io_fault_prefault_user(uio);
1037 if (error != 0)
1038 return (error); /* Or ignore ? */
1039 }
1040
1041 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ;
1042
1043 /*
1044 * The UFS follows IO_UNIT directive and replays back both
1045 * uio_offset and uio_resid if an error is encountered during the
1046 * operation. But, since the iovec may be already advanced,
1047 * uio is still in an inconsistent state.
1048 *
1049 * Cache a copy of the original uio, which is advanced to the redo
1050 * point using UIO_NOCOPY below.
1051 */
1052 uio_clone = cloneuio(uio);
1053 resid = uio->uio_resid;
1054
1055 short_uio.uio_segflg = UIO_USERSPACE;
1056 short_uio.uio_rw = uio->uio_rw;
1057 short_uio.uio_td = uio->uio_td;
1058
1059 save = vm_fault_disable_pagefaults();
1060 error = vn_io_fault_doio(args, uio, td);
1061 if (error != EFAULT)
1062 goto out;
1063
1064 atomic_add_long(&vn_io_faults_cnt, 1);
1065 uio_clone->uio_segflg = UIO_NOCOPY;
1066 uiomove(NULL, resid - uio->uio_resid, uio_clone);
1067 uio_clone->uio_segflg = uio->uio_segflg;
1068
1069 saveheld = curthread_pflags_set(TDP_UIOHELD);
1070 prev_td_ma = td->td_ma;
1071 prev_td_ma_cnt = td->td_ma_cnt;
1072
1073 while (uio_clone->uio_resid != 0) {
1074 len = uio_clone->uio_iov->iov_len;
1075 if (len == 0) {
1076 KASSERT(uio_clone->uio_iovcnt >= 1,
1077 ("iovcnt underflow"));
1078 uio_clone->uio_iov++;
1079 uio_clone->uio_iovcnt--;
1080 continue;
1081 }
1082 if (len > io_hold_cnt * PAGE_SIZE)
1083 len = io_hold_cnt * PAGE_SIZE;
1084 addr = (uintptr_t)uio_clone->uio_iov->iov_base;
1085 end = round_page(addr + len);
1086 if (end < addr) {
1087 error = EFAULT;
1088 break;
1089 }
1090 cnt = atop(end - trunc_page(addr));
1091 /*
1092 * A perfectly misaligned address and length could cause
1093 * both the start and the end of the chunk to use partial
1094 * page. +2 accounts for such a situation.
1095 */
1096 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map,
1097 addr, len, prot, ma, io_hold_cnt + 2);
1098 if (cnt == -1) {
1099 error = EFAULT;
1100 break;
1101 }
1102 short_uio.uio_iov = &short_iovec[0];
1103 short_iovec[0].iov_base = (void *)addr;
1104 short_uio.uio_iovcnt = 1;
1105 short_uio.uio_resid = short_iovec[0].iov_len = len;
1106 short_uio.uio_offset = uio_clone->uio_offset;
1107 td->td_ma = ma;
1108 td->td_ma_cnt = cnt;
1109
1110 error = vn_io_fault_doio(args, &short_uio, td);
1111 vm_page_unhold_pages(ma, cnt);
1112 adv = len - short_uio.uio_resid;
1113
1114 uio_clone->uio_iov->iov_base =
1115 (char *)uio_clone->uio_iov->iov_base + adv;
1116 uio_clone->uio_iov->iov_len -= adv;
1117 uio_clone->uio_resid -= adv;
1118 uio_clone->uio_offset += adv;
1119
1120 uio->uio_resid -= adv;
1121 uio->uio_offset += adv;
1122
1123 if (error != 0 || adv == 0)
1124 break;
1125 }
1126 td->td_ma = prev_td_ma;
1127 td->td_ma_cnt = prev_td_ma_cnt;
1128 curthread_pflags_restore(saveheld);
1129 out:
1130 vm_fault_enable_pagefaults(save);
1131 free(uio_clone, M_IOV);
1132 return (error);
1133 }
1134
1135 static int
1136 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred,
1137 int flags, struct thread *td)
1138 {
1139 fo_rdwr_t *doio;
1140 struct vnode *vp;
1141 void *rl_cookie;
1142 struct vn_io_fault_args args;
1143 int error;
1144
1145 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write;
1146 vp = fp->f_vnode;
1147 foffset_lock_uio(fp, uio, flags);
1148 if (do_vn_io_fault(vp, uio)) {
1149 args.kind = VN_IO_FAULT_FOP;
1150 args.args.fop_args.fp = fp;
1151 args.args.fop_args.doio = doio;
1152 args.cred = active_cred;
1153 args.flags = flags | FOF_OFFSET;
1154 if (uio->uio_rw == UIO_READ) {
1155 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset,
1156 uio->uio_offset + uio->uio_resid);
1157 } else if ((fp->f_flag & O_APPEND) != 0 ||
1158 (flags & FOF_OFFSET) == 0) {
1159 /* For appenders, punt and lock the whole range. */
1160 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1161 } else {
1162 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset,
1163 uio->uio_offset + uio->uio_resid);
1164 }
1165 error = vn_io_fault1(vp, uio, &args, td);
1166 vn_rangelock_unlock(vp, rl_cookie);
1167 } else {
1168 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td);
1169 }
1170 foffset_unlock_uio(fp, uio, flags);
1171 return (error);
1172 }
1173
1174 /*
1175 * Helper function to perform the requested uiomove operation using
1176 * the held pages for io->uio_iov[0].iov_base buffer instead of
1177 * copyin/copyout. Access to the pages with uiomove_fromphys()
1178 * instead of iov_base prevents page faults that could occur due to
1179 * pmap_collect() invalidating the mapping created by
1180 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or
1181 * object cleanup revoking the write access from page mappings.
1182 *
1183 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove()
1184 * instead of plain uiomove().
1185 */
1186 int
1187 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio)
1188 {
1189 struct uio transp_uio;
1190 struct iovec transp_iov[1];
1191 struct thread *td;
1192 size_t adv;
1193 int error, pgadv;
1194
1195 td = curthread;
1196 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1197 uio->uio_segflg != UIO_USERSPACE)
1198 return (uiomove(data, xfersize, uio));
1199
1200 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1201 transp_iov[0].iov_base = data;
1202 transp_uio.uio_iov = &transp_iov[0];
1203 transp_uio.uio_iovcnt = 1;
1204 if (xfersize > uio->uio_resid)
1205 xfersize = uio->uio_resid;
1206 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize;
1207 transp_uio.uio_offset = 0;
1208 transp_uio.uio_segflg = UIO_SYSSPACE;
1209 /*
1210 * Since transp_iov points to data, and td_ma page array
1211 * corresponds to original uio->uio_iov, we need to invert the
1212 * direction of the i/o operation as passed to
1213 * uiomove_fromphys().
1214 */
1215 switch (uio->uio_rw) {
1216 case UIO_WRITE:
1217 transp_uio.uio_rw = UIO_READ;
1218 break;
1219 case UIO_READ:
1220 transp_uio.uio_rw = UIO_WRITE;
1221 break;
1222 }
1223 transp_uio.uio_td = uio->uio_td;
1224 error = uiomove_fromphys(td->td_ma,
1225 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK,
1226 xfersize, &transp_uio);
1227 adv = xfersize - transp_uio.uio_resid;
1228 pgadv =
1229 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) -
1230 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT);
1231 td->td_ma += pgadv;
1232 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1233 pgadv));
1234 td->td_ma_cnt -= pgadv;
1235 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv;
1236 uio->uio_iov->iov_len -= adv;
1237 uio->uio_resid -= adv;
1238 uio->uio_offset += adv;
1239 return (error);
1240 }
1241
1242 int
1243 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize,
1244 struct uio *uio)
1245 {
1246 struct thread *td;
1247 vm_offset_t iov_base;
1248 int cnt, pgadv;
1249
1250 td = curthread;
1251 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1252 uio->uio_segflg != UIO_USERSPACE)
1253 return (uiomove_fromphys(ma, offset, xfersize, uio));
1254
1255 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1256 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize;
1257 iov_base = (vm_offset_t)uio->uio_iov->iov_base;
1258 switch (uio->uio_rw) {
1259 case UIO_WRITE:
1260 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma,
1261 offset, cnt);
1262 break;
1263 case UIO_READ:
1264 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK,
1265 cnt);
1266 break;
1267 }
1268 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT);
1269 td->td_ma += pgadv;
1270 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1271 pgadv));
1272 td->td_ma_cnt -= pgadv;
1273 uio->uio_iov->iov_base = (char *)(iov_base + cnt);
1274 uio->uio_iov->iov_len -= cnt;
1275 uio->uio_resid -= cnt;
1276 uio->uio_offset += cnt;
1277 return (0);
1278 }
1279
1280
1281 /*
1282 * File table truncate routine.
1283 */
1284 static int
1285 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred,
1286 struct thread *td)
1287 {
1288 struct vattr vattr;
1289 struct mount *mp;
1290 struct vnode *vp;
1291 void *rl_cookie;
1292 int error;
1293
1294 vp = fp->f_vnode;
1295
1296 /*
1297 * Lock the whole range for truncation. Otherwise split i/o
1298 * might happen partly before and partly after the truncation.
1299 */
1300 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1301 error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
1302 if (error)
1303 goto out1;
1304 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1305 if (vp->v_type == VDIR) {
1306 error = EISDIR;
1307 goto out;
1308 }
1309 #ifdef MAC
1310 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
1311 if (error)
1312 goto out;
1313 #endif
1314 error = vn_writechk(vp);
1315 if (error == 0) {
1316 VATTR_NULL(&vattr);
1317 vattr.va_size = length;
1318 if ((fp->f_flag & O_FSYNC) != 0)
1319 vattr.va_vaflags |= VA_SYNC;
1320 error = VOP_SETATTR(vp, &vattr, fp->f_cred);
1321 }
1322 out:
1323 VOP_UNLOCK(vp, 0);
1324 vn_finished_write(mp);
1325 out1:
1326 vn_rangelock_unlock(vp, rl_cookie);
1327 return (error);
1328 }
1329
1330 /*
1331 * File table vnode stat routine.
1332 */
1333 static int
1334 vn_statfile(fp, sb, active_cred, td)
1335 struct file *fp;
1336 struct stat *sb;
1337 struct ucred *active_cred;
1338 struct thread *td;
1339 {
1340 struct vnode *vp = fp->f_vnode;
1341 int error;
1342
1343 vn_lock(vp, LK_SHARED | LK_RETRY);
1344 error = vn_stat(vp, sb, active_cred, fp->f_cred, td);
1345 VOP_UNLOCK(vp, 0);
1346
1347 return (error);
1348 }
1349
1350 /*
1351 * Stat a vnode; implementation for the stat syscall
1352 */
1353 int
1354 vn_stat(vp, sb, active_cred, file_cred, td)
1355 struct vnode *vp;
1356 register struct stat *sb;
1357 struct ucred *active_cred;
1358 struct ucred *file_cred;
1359 struct thread *td;
1360 {
1361 struct vattr vattr;
1362 register struct vattr *vap;
1363 int error;
1364 u_short mode;
1365
1366 AUDIT_ARG_VNODE1(vp);
1367 #ifdef MAC
1368 error = mac_vnode_check_stat(active_cred, file_cred, vp);
1369 if (error)
1370 return (error);
1371 #endif
1372
1373 vap = &vattr;
1374
1375 /*
1376 * Initialize defaults for new and unusual fields, so that file
1377 * systems which don't support these fields don't need to know
1378 * about them.
1379 */
1380 vap->va_birthtime.tv_sec = -1;
1381 vap->va_birthtime.tv_nsec = 0;
1382 vap->va_fsid = VNOVAL;
1383 vap->va_rdev = NODEV;
1384
1385 error = VOP_GETATTR(vp, vap, active_cred);
1386 if (error)
1387 return (error);
1388
1389 /*
1390 * Zero the spare stat fields
1391 */
1392 bzero(sb, sizeof *sb);
1393
1394 /*
1395 * Copy from vattr table
1396 */
1397 if (vap->va_fsid != VNOVAL)
1398 sb->st_dev = vap->va_fsid;
1399 else
1400 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
1401 sb->st_ino = vap->va_fileid;
1402 mode = vap->va_mode;
1403 switch (vap->va_type) {
1404 case VREG:
1405 mode |= S_IFREG;
1406 break;
1407 case VDIR:
1408 mode |= S_IFDIR;
1409 break;
1410 case VBLK:
1411 mode |= S_IFBLK;
1412 break;
1413 case VCHR:
1414 mode |= S_IFCHR;
1415 break;
1416 case VLNK:
1417 mode |= S_IFLNK;
1418 break;
1419 case VSOCK:
1420 mode |= S_IFSOCK;
1421 break;
1422 case VFIFO:
1423 mode |= S_IFIFO;
1424 break;
1425 default:
1426 return (EBADF);
1427 }
1428 sb->st_mode = mode;
1429 sb->st_nlink = vap->va_nlink;
1430 sb->st_uid = vap->va_uid;
1431 sb->st_gid = vap->va_gid;
1432 sb->st_rdev = vap->va_rdev;
1433 if (vap->va_size > OFF_MAX)
1434 return (EOVERFLOW);
1435 sb->st_size = vap->va_size;
1436 sb->st_atim = vap->va_atime;
1437 sb->st_mtim = vap->va_mtime;
1438 sb->st_ctim = vap->va_ctime;
1439 sb->st_birthtim = vap->va_birthtime;
1440
1441 /*
1442 * According to www.opengroup.org, the meaning of st_blksize is
1443 * "a filesystem-specific preferred I/O block size for this
1444 * object. In some filesystem types, this may vary from file
1445 * to file"
1446 * Use miminum/default of PAGE_SIZE (e.g. for VCHR).
1447 */
1448
1449 sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize);
1450
1451 sb->st_flags = vap->va_flags;
1452 if (priv_check(td, PRIV_VFS_GENERATION))
1453 sb->st_gen = 0;
1454 else
1455 sb->st_gen = vap->va_gen;
1456
1457 sb->st_blocks = vap->va_bytes / S_BLKSIZE;
1458 return (0);
1459 }
1460
1461 /*
1462 * File table vnode ioctl routine.
1463 */
1464 static int
1465 vn_ioctl(fp, com, data, active_cred, td)
1466 struct file *fp;
1467 u_long com;
1468 void *data;
1469 struct ucred *active_cred;
1470 struct thread *td;
1471 {
1472 struct vattr vattr;
1473 struct vnode *vp;
1474 int error;
1475
1476 vp = fp->f_vnode;
1477 switch (vp->v_type) {
1478 case VDIR:
1479 case VREG:
1480 switch (com) {
1481 case FIONREAD:
1482 vn_lock(vp, LK_SHARED | LK_RETRY);
1483 error = VOP_GETATTR(vp, &vattr, active_cred);
1484 VOP_UNLOCK(vp, 0);
1485 if (error == 0)
1486 *(int *)data = vattr.va_size - fp->f_offset;
1487 return (error);
1488 case FIONBIO:
1489 case FIOASYNC:
1490 return (0);
1491 default:
1492 return (VOP_IOCTL(vp, com, data, fp->f_flag,
1493 active_cred, td));
1494 }
1495 default:
1496 return (ENOTTY);
1497 }
1498 }
1499
1500 /*
1501 * File table vnode poll routine.
1502 */
1503 static int
1504 vn_poll(fp, events, active_cred, td)
1505 struct file *fp;
1506 int events;
1507 struct ucred *active_cred;
1508 struct thread *td;
1509 {
1510 struct vnode *vp;
1511 int error;
1512
1513 vp = fp->f_vnode;
1514 #ifdef MAC
1515 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1516 AUDIT_ARG_VNODE1(vp);
1517 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp);
1518 VOP_UNLOCK(vp, 0);
1519 if (!error)
1520 #endif
1521
1522 error = VOP_POLL(vp, events, fp->f_cred, td);
1523 return (error);
1524 }
1525
1526 /*
1527 * Acquire the requested lock and then check for validity. LK_RETRY
1528 * permits vn_lock to return doomed vnodes.
1529 */
1530 int
1531 _vn_lock(struct vnode *vp, int flags, char *file, int line)
1532 {
1533 int error;
1534
1535 VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
1536 ("vn_lock called with no locktype."));
1537 do {
1538 #ifdef DEBUG_VFS_LOCKS
1539 KASSERT(vp->v_holdcnt != 0,
1540 ("vn_lock %p: zero hold count", vp));
1541 #endif
1542 error = VOP_LOCK1(vp, flags, file, line);
1543 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */
1544 KASSERT((flags & LK_RETRY) == 0 || error == 0,
1545 ("LK_RETRY set with incompatible flags (0x%x) or an error occurred (%d)",
1546 flags, error));
1547 /*
1548 * Callers specify LK_RETRY if they wish to get dead vnodes.
1549 * If RETRY is not set, we return ENOENT instead.
1550 */
1551 if (error == 0 && vp->v_iflag & VI_DOOMED &&
1552 (flags & LK_RETRY) == 0) {
1553 VOP_UNLOCK(vp, 0);
1554 error = ENOENT;
1555 break;
1556 }
1557 } while (flags & LK_RETRY && error != 0);
1558 return (error);
1559 }
1560
1561 /*
1562 * File table vnode close routine.
1563 */
1564 static int
1565 vn_closefile(fp, td)
1566 struct file *fp;
1567 struct thread *td;
1568 {
1569 struct vnode *vp;
1570 struct flock lf;
1571 int error;
1572
1573 vp = fp->f_vnode;
1574 fp->f_ops = &badfileops;
1575
1576 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK)
1577 vref(vp);
1578
1579 error = vn_close(vp, fp->f_flag, fp->f_cred, td);
1580
1581 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) {
1582 lf.l_whence = SEEK_SET;
1583 lf.l_start = 0;
1584 lf.l_len = 0;
1585 lf.l_type = F_UNLCK;
1586 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK);
1587 vrele(vp);
1588 }
1589 return (error);
1590 }
1591
1592 static bool
1593 vn_suspendable(struct mount *mp)
1594 {
1595
1596 return (mp->mnt_op->vfs_susp_clean != NULL);
1597 }
1598
1599 /*
1600 * Preparing to start a filesystem write operation. If the operation is
1601 * permitted, then we bump the count of operations in progress and
1602 * proceed. If a suspend request is in progress, we wait until the
1603 * suspension is over, and then proceed.
1604 */
1605 static int
1606 vn_start_write_locked(struct mount *mp, int flags)
1607 {
1608 int error, mflags;
1609
1610 mtx_assert(MNT_MTX(mp), MA_OWNED);
1611 error = 0;
1612
1613 /*
1614 * Check on status of suspension.
1615 */
1616 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 ||
1617 mp->mnt_susp_owner != curthread) {
1618 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ?
1619 (flags & PCATCH) : 0) | (PUSER - 1);
1620 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1621 if (flags & V_NOWAIT) {
1622 error = EWOULDBLOCK;
1623 goto unlock;
1624 }
1625 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags,
1626 "suspfs", 0);
1627 if (error)
1628 goto unlock;
1629 }
1630 }
1631 if (flags & V_XSLEEP)
1632 goto unlock;
1633 mp->mnt_writeopcount++;
1634 unlock:
1635 if (error != 0 || (flags & V_XSLEEP) != 0)
1636 MNT_REL(mp);
1637 MNT_IUNLOCK(mp);
1638 return (error);
1639 }
1640
1641 int
1642 vn_start_write(struct vnode *vp, struct mount **mpp, int flags)
1643 {
1644 struct mount *mp;
1645 int error;
1646
1647 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1648 ("V_MNTREF requires mp"));
1649
1650 error = 0;
1651 /*
1652 * If a vnode is provided, get and return the mount point that
1653 * to which it will write.
1654 */
1655 if (vp != NULL) {
1656 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1657 *mpp = NULL;
1658 if (error != EOPNOTSUPP)
1659 return (error);
1660 return (0);
1661 }
1662 }
1663 if ((mp = *mpp) == NULL)
1664 return (0);
1665
1666 if (!vn_suspendable(mp)) {
1667 if (vp != NULL || (flags & V_MNTREF) != 0)
1668 vfs_rel(mp);
1669 return (0);
1670 }
1671
1672 /*
1673 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1674 * a vfs_ref().
1675 * As long as a vnode is not provided we need to acquire a
1676 * refcount for the provided mountpoint too, in order to
1677 * emulate a vfs_ref().
1678 */
1679 MNT_ILOCK(mp);
1680 if (vp == NULL && (flags & V_MNTREF) == 0)
1681 MNT_REF(mp);
1682
1683 return (vn_start_write_locked(mp, flags));
1684 }
1685
1686 /*
1687 * Secondary suspension. Used by operations such as vop_inactive
1688 * routines that are needed by the higher level functions. These
1689 * are allowed to proceed until all the higher level functions have
1690 * completed (indicated by mnt_writeopcount dropping to zero). At that
1691 * time, these operations are halted until the suspension is over.
1692 */
1693 int
1694 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags)
1695 {
1696 struct mount *mp;
1697 int error;
1698
1699 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1700 ("V_MNTREF requires mp"));
1701
1702 retry:
1703 if (vp != NULL) {
1704 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1705 *mpp = NULL;
1706 if (error != EOPNOTSUPP)
1707 return (error);
1708 return (0);
1709 }
1710 }
1711 /*
1712 * If we are not suspended or have not yet reached suspended
1713 * mode, then let the operation proceed.
1714 */
1715 if ((mp = *mpp) == NULL)
1716 return (0);
1717
1718 if (!vn_suspendable(mp)) {
1719 if (vp != NULL || (flags & V_MNTREF) != 0)
1720 vfs_rel(mp);
1721 return (0);
1722 }
1723
1724 /*
1725 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1726 * a vfs_ref().
1727 * As long as a vnode is not provided we need to acquire a
1728 * refcount for the provided mountpoint too, in order to
1729 * emulate a vfs_ref().
1730 */
1731 MNT_ILOCK(mp);
1732 if (vp == NULL && (flags & V_MNTREF) == 0)
1733 MNT_REF(mp);
1734 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
1735 mp->mnt_secondary_writes++;
1736 mp->mnt_secondary_accwrites++;
1737 MNT_IUNLOCK(mp);
1738 return (0);
1739 }
1740 if (flags & V_NOWAIT) {
1741 MNT_REL(mp);
1742 MNT_IUNLOCK(mp);
1743 return (EWOULDBLOCK);
1744 }
1745 /*
1746 * Wait for the suspension to finish.
1747 */
1748 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP |
1749 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0),
1750 "suspfs", 0);
1751 vfs_rel(mp);
1752 if (error == 0)
1753 goto retry;
1754 return (error);
1755 }
1756
1757 /*
1758 * Filesystem write operation has completed. If we are suspending and this
1759 * operation is the last one, notify the suspender that the suspension is
1760 * now in effect.
1761 */
1762 void
1763 vn_finished_write(mp)
1764 struct mount *mp;
1765 {
1766 if (mp == NULL || !vn_suspendable(mp))
1767 return;
1768 MNT_ILOCK(mp);
1769 MNT_REL(mp);
1770 mp->mnt_writeopcount--;
1771 if (mp->mnt_writeopcount < 0)
1772 panic("vn_finished_write: neg cnt");
1773 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1774 mp->mnt_writeopcount <= 0)
1775 wakeup(&mp->mnt_writeopcount);
1776 MNT_IUNLOCK(mp);
1777 }
1778
1779
1780 /*
1781 * Filesystem secondary write operation has completed. If we are
1782 * suspending and this operation is the last one, notify the suspender
1783 * that the suspension is now in effect.
1784 */
1785 void
1786 vn_finished_secondary_write(mp)
1787 struct mount *mp;
1788 {
1789 if (mp == NULL || !vn_suspendable(mp))
1790 return;
1791 MNT_ILOCK(mp);
1792 MNT_REL(mp);
1793 mp->mnt_secondary_writes--;
1794 if (mp->mnt_secondary_writes < 0)
1795 panic("vn_finished_secondary_write: neg cnt");
1796 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1797 mp->mnt_secondary_writes <= 0)
1798 wakeup(&mp->mnt_secondary_writes);
1799 MNT_IUNLOCK(mp);
1800 }
1801
1802
1803
1804 /*
1805 * Request a filesystem to suspend write operations.
1806 */
1807 int
1808 vfs_write_suspend(struct mount *mp, int flags)
1809 {
1810 int error;
1811
1812 MPASS(vn_suspendable(mp));
1813
1814 MNT_ILOCK(mp);
1815 if (mp->mnt_susp_owner == curthread) {
1816 MNT_IUNLOCK(mp);
1817 return (EALREADY);
1818 }
1819 while (mp->mnt_kern_flag & MNTK_SUSPEND)
1820 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0);
1821
1822 /*
1823 * Unmount holds a write reference on the mount point. If we
1824 * own busy reference and drain for writers, we deadlock with
1825 * the reference draining in the unmount path. Callers of
1826 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if
1827 * vfs_busy() reference is owned and caller is not in the
1828 * unmount context.
1829 */
1830 if ((flags & VS_SKIP_UNMOUNT) != 0 &&
1831 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
1832 MNT_IUNLOCK(mp);
1833 return (EBUSY);
1834 }
1835
1836 mp->mnt_kern_flag |= MNTK_SUSPEND;
1837 mp->mnt_susp_owner = curthread;
1838 if (mp->mnt_writeopcount > 0)
1839 (void) msleep(&mp->mnt_writeopcount,
1840 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0);
1841 else
1842 MNT_IUNLOCK(mp);
1843 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0)
1844 vfs_write_resume(mp, 0);
1845 return (error);
1846 }
1847
1848 /*
1849 * Request a filesystem to resume write operations.
1850 */
1851 void
1852 vfs_write_resume(struct mount *mp, int flags)
1853 {
1854
1855 MPASS(vn_suspendable(mp));
1856
1857 MNT_ILOCK(mp);
1858 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1859 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
1860 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 |
1861 MNTK_SUSPENDED);
1862 mp->mnt_susp_owner = NULL;
1863 wakeup(&mp->mnt_writeopcount);
1864 wakeup(&mp->mnt_flag);
1865 curthread->td_pflags &= ~TDP_IGNSUSP;
1866 if ((flags & VR_START_WRITE) != 0) {
1867 MNT_REF(mp);
1868 mp->mnt_writeopcount++;
1869 }
1870 MNT_IUNLOCK(mp);
1871 if ((flags & VR_NO_SUSPCLR) == 0)
1872 VFS_SUSP_CLEAN(mp);
1873 } else if ((flags & VR_START_WRITE) != 0) {
1874 MNT_REF(mp);
1875 vn_start_write_locked(mp, 0);
1876 } else {
1877 MNT_IUNLOCK(mp);
1878 }
1879 }
1880
1881 /*
1882 * Helper loop around vfs_write_suspend() for filesystem unmount VFS
1883 * methods.
1884 */
1885 int
1886 vfs_write_suspend_umnt(struct mount *mp)
1887 {
1888 int error;
1889
1890 MPASS(vn_suspendable(mp));
1891 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
1892 ("vfs_write_suspend_umnt: recursed"));
1893
1894 /* dounmount() already called vn_start_write(). */
1895 for (;;) {
1896 vn_finished_write(mp);
1897 error = vfs_write_suspend(mp, 0);
1898 if (error != 0) {
1899 vn_start_write(NULL, &mp, V_WAIT);
1900 return (error);
1901 }
1902 MNT_ILOCK(mp);
1903 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0)
1904 break;
1905 MNT_IUNLOCK(mp);
1906 vn_start_write(NULL, &mp, V_WAIT);
1907 }
1908 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2);
1909 wakeup(&mp->mnt_flag);
1910 MNT_IUNLOCK(mp);
1911 curthread->td_pflags |= TDP_IGNSUSP;
1912 return (0);
1913 }
1914
1915 /*
1916 * Implement kqueues for files by translating it to vnode operation.
1917 */
1918 static int
1919 vn_kqfilter(struct file *fp, struct knote *kn)
1920 {
1921
1922 return (VOP_KQFILTER(fp->f_vnode, kn));
1923 }
1924
1925 /*
1926 * Simplified in-kernel wrapper calls for extended attribute access.
1927 * Both calls pass in a NULL credential, authorizing as "kernel" access.
1928 * Set IO_NODELOCKED in ioflg if the vnode is already locked.
1929 */
1930 int
1931 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace,
1932 const char *attrname, int *buflen, char *buf, struct thread *td)
1933 {
1934 struct uio auio;
1935 struct iovec iov;
1936 int error;
1937
1938 iov.iov_len = *buflen;
1939 iov.iov_base = buf;
1940
1941 auio.uio_iov = &iov;
1942 auio.uio_iovcnt = 1;
1943 auio.uio_rw = UIO_READ;
1944 auio.uio_segflg = UIO_SYSSPACE;
1945 auio.uio_td = td;
1946 auio.uio_offset = 0;
1947 auio.uio_resid = *buflen;
1948
1949 if ((ioflg & IO_NODELOCKED) == 0)
1950 vn_lock(vp, LK_SHARED | LK_RETRY);
1951
1952 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
1953
1954 /* authorize attribute retrieval as kernel */
1955 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL,
1956 td);
1957
1958 if ((ioflg & IO_NODELOCKED) == 0)
1959 VOP_UNLOCK(vp, 0);
1960
1961 if (error == 0) {
1962 *buflen = *buflen - auio.uio_resid;
1963 }
1964
1965 return (error);
1966 }
1967
1968 /*
1969 * XXX failure mode if partially written?
1970 */
1971 int
1972 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace,
1973 const char *attrname, int buflen, char *buf, struct thread *td)
1974 {
1975 struct uio auio;
1976 struct iovec iov;
1977 struct mount *mp;
1978 int error;
1979
1980 iov.iov_len = buflen;
1981 iov.iov_base = buf;
1982
1983 auio.uio_iov = &iov;
1984 auio.uio_iovcnt = 1;
1985 auio.uio_rw = UIO_WRITE;
1986 auio.uio_segflg = UIO_SYSSPACE;
1987 auio.uio_td = td;
1988 auio.uio_offset = 0;
1989 auio.uio_resid = buflen;
1990
1991 if ((ioflg & IO_NODELOCKED) == 0) {
1992 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
1993 return (error);
1994 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1995 }
1996
1997 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
1998
1999 /* authorize attribute setting as kernel */
2000 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td);
2001
2002 if ((ioflg & IO_NODELOCKED) == 0) {
2003 vn_finished_write(mp);
2004 VOP_UNLOCK(vp, 0);
2005 }
2006
2007 return (error);
2008 }
2009
2010 int
2011 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
2012 const char *attrname, struct thread *td)
2013 {
2014 struct mount *mp;
2015 int error;
2016
2017 if ((ioflg & IO_NODELOCKED) == 0) {
2018 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2019 return (error);
2020 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2021 }
2022
2023 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2024
2025 /* authorize attribute removal as kernel */
2026 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td);
2027 if (error == EOPNOTSUPP)
2028 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL,
2029 NULL, td);
2030
2031 if ((ioflg & IO_NODELOCKED) == 0) {
2032 vn_finished_write(mp);
2033 VOP_UNLOCK(vp, 0);
2034 }
2035
2036 return (error);
2037 }
2038
2039 static int
2040 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags,
2041 struct vnode **rvp)
2042 {
2043
2044 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp));
2045 }
2046
2047 int
2048 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp)
2049 {
2050
2051 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino,
2052 lkflags, rvp));
2053 }
2054
2055 int
2056 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg,
2057 int lkflags, struct vnode **rvp)
2058 {
2059 struct mount *mp;
2060 int ltype, error;
2061
2062 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get");
2063 mp = vp->v_mount;
2064 ltype = VOP_ISLOCKED(vp);
2065 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED,
2066 ("vn_vget_ino: vp not locked"));
2067 error = vfs_busy(mp, MBF_NOWAIT);
2068 if (error != 0) {
2069 vfs_ref(mp);
2070 VOP_UNLOCK(vp, 0);
2071 error = vfs_busy(mp, 0);
2072 vn_lock(vp, ltype | LK_RETRY);
2073 vfs_rel(mp);
2074 if (error != 0)
2075 return (ENOENT);
2076 if (vp->v_iflag & VI_DOOMED) {
2077 vfs_unbusy(mp);
2078 return (ENOENT);
2079 }
2080 }
2081 VOP_UNLOCK(vp, 0);
2082 error = alloc(mp, alloc_arg, lkflags, rvp);
2083 vfs_unbusy(mp);
2084 if (*rvp != vp)
2085 vn_lock(vp, ltype | LK_RETRY);
2086 if (vp->v_iflag & VI_DOOMED) {
2087 if (error == 0) {
2088 if (*rvp == vp)
2089 vunref(vp);
2090 else
2091 vput(*rvp);
2092 }
2093 error = ENOENT;
2094 }
2095 return (error);
2096 }
2097
2098 int
2099 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
2100 struct thread *td)
2101 {
2102
2103 if (vp->v_type != VREG || td == NULL)
2104 return (0);
2105 if ((uoff_t)uio->uio_offset + uio->uio_resid >
2106 lim_cur(td, RLIMIT_FSIZE)) {
2107 PROC_LOCK(td->td_proc);
2108 kern_psignal(td->td_proc, SIGXFSZ);
2109 PROC_UNLOCK(td->td_proc);
2110 return (EFBIG);
2111 }
2112 return (0);
2113 }
2114
2115 int
2116 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
2117 struct thread *td)
2118 {
2119 struct vnode *vp;
2120
2121 vp = fp->f_vnode;
2122 #ifdef AUDIT
2123 vn_lock(vp, LK_SHARED | LK_RETRY);
2124 AUDIT_ARG_VNODE1(vp);
2125 VOP_UNLOCK(vp, 0);
2126 #endif
2127 return (setfmode(td, active_cred, vp, mode));
2128 }
2129
2130 int
2131 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
2132 struct thread *td)
2133 {
2134 struct vnode *vp;
2135
2136 vp = fp->f_vnode;
2137 #ifdef AUDIT
2138 vn_lock(vp, LK_SHARED | LK_RETRY);
2139 AUDIT_ARG_VNODE1(vp);
2140 VOP_UNLOCK(vp, 0);
2141 #endif
2142 return (setfown(td, active_cred, vp, uid, gid));
2143 }
2144
2145 void
2146 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
2147 {
2148 vm_object_t object;
2149
2150 if ((object = vp->v_object) == NULL)
2151 return;
2152 VM_OBJECT_WLOCK(object);
2153 vm_object_page_remove(object, start, end, 0);
2154 VM_OBJECT_WUNLOCK(object);
2155 }
2156
2157 int
2158 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
2159 {
2160 struct vattr va;
2161 daddr_t bn, bnp;
2162 uint64_t bsize;
2163 off_t noff;
2164 int error;
2165
2166 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
2167 ("Wrong command %lu", cmd));
2168
2169 if (vn_lock(vp, LK_SHARED) != 0)
2170 return (EBADF);
2171 if (vp->v_type != VREG) {
2172 error = ENOTTY;
2173 goto unlock;
2174 }
2175 error = VOP_GETATTR(vp, &va, cred);
2176 if (error != 0)
2177 goto unlock;
2178 noff = *off;
2179 if (noff >= va.va_size) {
2180 error = ENXIO;
2181 goto unlock;
2182 }
2183 bsize = vp->v_mount->mnt_stat.f_iosize;
2184 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize) {
2185 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL);
2186 if (error == EOPNOTSUPP) {
2187 error = ENOTTY;
2188 goto unlock;
2189 }
2190 if ((bnp == -1 && cmd == FIOSEEKHOLE) ||
2191 (bnp != -1 && cmd == FIOSEEKDATA)) {
2192 noff = bn * bsize;
2193 if (noff < *off)
2194 noff = *off;
2195 goto unlock;
2196 }
2197 }
2198 if (noff > va.va_size)
2199 noff = va.va_size;
2200 /* noff == va.va_size. There is an implicit hole at the end of file. */
2201 if (cmd == FIOSEEKDATA)
2202 error = ENXIO;
2203 unlock:
2204 VOP_UNLOCK(vp, 0);
2205 if (error == 0)
2206 *off = noff;
2207 return (error);
2208 }
2209
2210 int
2211 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
2212 {
2213 struct ucred *cred;
2214 struct vnode *vp;
2215 struct vattr vattr;
2216 off_t foffset, size;
2217 int error, noneg;
2218
2219 cred = td->td_ucred;
2220 vp = fp->f_vnode;
2221 foffset = foffset_lock(fp, 0);
2222 noneg = (vp->v_type != VCHR);
2223 error = 0;
2224 switch (whence) {
2225 case L_INCR:
2226 if (noneg &&
2227 (foffset < 0 ||
2228 (offset > 0 && foffset > OFF_MAX - offset))) {
2229 error = EOVERFLOW;
2230 break;
2231 }
2232 offset += foffset;
2233 break;
2234 case L_XTND:
2235 vn_lock(vp, LK_SHARED | LK_RETRY);
2236 error = VOP_GETATTR(vp, &vattr, cred);
2237 VOP_UNLOCK(vp, 0);
2238 if (error)
2239 break;
2240
2241 /*
2242 * If the file references a disk device, then fetch
2243 * the media size and use that to determine the ending
2244 * offset.
2245 */
2246 if (vattr.va_size == 0 && vp->v_type == VCHR &&
2247 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0)
2248 vattr.va_size = size;
2249 if (noneg &&
2250 (vattr.va_size > OFF_MAX ||
2251 (offset > 0 && vattr.va_size > OFF_MAX - offset))) {
2252 error = EOVERFLOW;
2253 break;
2254 }
2255 offset += vattr.va_size;
2256 break;
2257 case L_SET:
2258 break;
2259 case SEEK_DATA:
2260 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td);
2261 break;
2262 case SEEK_HOLE:
2263 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td);
2264 break;
2265 default:
2266 error = EINVAL;
2267 }
2268 if (error == 0 && noneg && offset < 0)
2269 error = EINVAL;
2270 if (error != 0)
2271 goto drop;
2272 VFS_KNOTE_UNLOCKED(vp, 0);
2273 td->td_uretoff.tdu_off = offset;
2274 drop:
2275 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
2276 return (error);
2277 }
2278
2279 int
2280 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred,
2281 struct thread *td)
2282 {
2283 int error;
2284
2285 /*
2286 * Grant permission if the caller is the owner of the file, or
2287 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on
2288 * on the file. If the time pointer is null, then write
2289 * permission on the file is also sufficient.
2290 *
2291 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes:
2292 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES
2293 * will be allowed to set the times [..] to the current
2294 * server time.
2295 */
2296 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td);
2297 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0)
2298 error = VOP_ACCESS(vp, VWRITE, cred, td);
2299 return (error);
2300 }
2301
2302 int
2303 vn_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp)
2304 {
2305 struct vnode *vp;
2306 int error;
2307
2308 if (fp->f_type == DTYPE_FIFO)
2309 kif->kf_type = KF_TYPE_FIFO;
2310 else
2311 kif->kf_type = KF_TYPE_VNODE;
2312 vp = fp->f_vnode;
2313 vref(vp);
2314 FILEDESC_SUNLOCK(fdp);
2315 error = vn_fill_kinfo_vnode(vp, kif);
2316 vrele(vp);
2317 FILEDESC_SLOCK(fdp);
2318 return (error);
2319 }
2320
2321 static inline void
2322 vn_fill_junk(struct kinfo_file *kif)
2323 {
2324 size_t len, olen;
2325
2326 /*
2327 * Simulate vn_fullpath returning changing values for a given
2328 * vp during e.g. coredump.
2329 */
2330 len = (arc4random() % (sizeof(kif->kf_path) - 2)) + 1;
2331 olen = strlen(kif->kf_path);
2332 if (len < olen)
2333 strcpy(&kif->kf_path[len - 1], "$");
2334 else
2335 for (; olen < len; olen++)
2336 strcpy(&kif->kf_path[olen], "A");
2337 }
2338
2339 int
2340 vn_fill_kinfo_vnode(struct vnode *vp, struct kinfo_file *kif)
2341 {
2342 struct vattr va;
2343 char *fullpath, *freepath;
2344 int error;
2345
2346 kif->kf_vnode_type = vntype_to_kinfo(vp->v_type);
2347 freepath = NULL;
2348 fullpath = "-";
2349 error = vn_fullpath(curthread, vp, &fullpath, &freepath);
2350 if (error == 0) {
2351 strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path));
2352 }
2353 if (freepath != NULL)
2354 free(freepath, M_TEMP);
2355
2356 KFAIL_POINT_CODE(DEBUG_FP, fill_kinfo_vnode__random_path,
2357 vn_fill_junk(kif);
2358 );
2359
2360 /*
2361 * Retrieve vnode attributes.
2362 */
2363 va.va_fsid = VNOVAL;
2364 va.va_rdev = NODEV;
2365 vn_lock(vp, LK_SHARED | LK_RETRY);
2366 error = VOP_GETATTR(vp, &va, curthread->td_ucred);
2367 VOP_UNLOCK(vp, 0);
2368 if (error != 0)
2369 return (error);
2370 if (va.va_fsid != VNOVAL)
2371 kif->kf_un.kf_file.kf_file_fsid = va.va_fsid;
2372 else
2373 kif->kf_un.kf_file.kf_file_fsid =
2374 vp->v_mount->mnt_stat.f_fsid.val[0];
2375 kif->kf_un.kf_file.kf_file_fileid = va.va_fileid;
2376 kif->kf_un.kf_file.kf_file_mode = MAKEIMODE(va.va_type, va.va_mode);
2377 kif->kf_un.kf_file.kf_file_size = va.va_size;
2378 kif->kf_un.kf_file.kf_file_rdev = va.va_rdev;
2379 return (0);
2380 }
2381
2382 int
2383 vn_mmap(struct file *fp, vm_map_t map, vm_offset_t *addr, vm_size_t size,
2384 vm_prot_t prot, vm_prot_t cap_maxprot, int flags, vm_ooffset_t foff,
2385 struct thread *td)
2386 {
2387 #ifdef HWPMC_HOOKS
2388 struct pmckern_map_in pkm;
2389 #endif
2390 struct mount *mp;
2391 struct vnode *vp;
2392 vm_object_t object;
2393 vm_prot_t maxprot;
2394 boolean_t writecounted;
2395 int error;
2396
2397 #if defined(COMPAT_FREEBSD7) || defined(COMPAT_FREEBSD6) || \
2398 defined(COMPAT_FREEBSD5) || defined(COMPAT_FREEBSD4)
2399 /*
2400 * POSIX shared-memory objects are defined to have
2401 * kernel persistence, and are not defined to support
2402 * read(2)/write(2) -- or even open(2). Thus, we can
2403 * use MAP_ASYNC to trade on-disk coherence for speed.
2404 * The shm_open(3) library routine turns on the FPOSIXSHM
2405 * flag to request this behavior.
2406 */
2407 if ((fp->f_flag & FPOSIXSHM) != 0)
2408 flags |= MAP_NOSYNC;
2409 #endif
2410 vp = fp->f_vnode;
2411
2412 /*
2413 * Ensure that file and memory protections are
2414 * compatible. Note that we only worry about
2415 * writability if mapping is shared; in this case,
2416 * current and max prot are dictated by the open file.
2417 * XXX use the vnode instead? Problem is: what
2418 * credentials do we use for determination? What if
2419 * proc does a setuid?
2420 */
2421 mp = vp->v_mount;
2422 if (mp != NULL && (mp->mnt_flag & MNT_NOEXEC) != 0)
2423 maxprot = VM_PROT_NONE;
2424 else
2425 maxprot = VM_PROT_EXECUTE;
2426 if ((fp->f_flag & FREAD) != 0)
2427 maxprot |= VM_PROT_READ;
2428 else if ((prot & VM_PROT_READ) != 0)
2429 return (EACCES);
2430
2431 /*
2432 * If we are sharing potential changes via MAP_SHARED and we
2433 * are trying to get write permission although we opened it
2434 * without asking for it, bail out.
2435 */
2436 if ((flags & MAP_SHARED) != 0) {
2437 if ((fp->f_flag & FWRITE) != 0)
2438 maxprot |= VM_PROT_WRITE;
2439 else if ((prot & VM_PROT_WRITE) != 0)
2440 return (EACCES);
2441 } else {
2442 maxprot |= VM_PROT_WRITE;
2443 cap_maxprot |= VM_PROT_WRITE;
2444 }
2445 maxprot &= cap_maxprot;
2446
2447 writecounted = FALSE;
2448 error = vm_mmap_vnode(td, size, prot, &maxprot, &flags, vp,
2449 &foff, &object, &writecounted);
2450 if (error != 0)
2451 return (error);
2452 error = vm_mmap_object(map, addr, size, prot, maxprot, flags, object,
2453 foff, writecounted, td);
2454 if (error != 0) {
2455 /*
2456 * If this mapping was accounted for in the vnode's
2457 * writecount, then undo that now.
2458 */
2459 if (writecounted)
2460 vnode_pager_release_writecount(object, 0, size);
2461 vm_object_deallocate(object);
2462 }
2463 #ifdef HWPMC_HOOKS
2464 /* Inform hwpmc(4) if an executable is being mapped. */
2465 if (error == 0 && (prot & VM_PROT_EXECUTE) != 0) {
2466 pkm.pm_file = vp;
2467 pkm.pm_address = (uintptr_t) *addr;
2468 PMC_CALL_HOOK(td, PMC_FN_MMAP, (void *) &pkm);
2469 }
2470 #endif
2471 return (error);
2472 }
Cache object: 56eb1d868913307fc465659f4a55fb99
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