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/10.3/sys/kern/vfs_vnops.c 295614 2016-02-14 18:17:58Z kib $");
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/mount.h>
58 #include <sys/mutex.h>
59 #include <sys/namei.h>
60 #include <sys/vnode.h>
61 #include <sys/bio.h>
62 #include <sys/buf.h>
63 #include <sys/filio.h>
64 #include <sys/resourcevar.h>
65 #include <sys/rwlock.h>
66 #include <sys/sx.h>
67 #include <sys/sysctl.h>
68 #include <sys/ttycom.h>
69 #include <sys/conf.h>
70 #include <sys/syslog.h>
71 #include <sys/unistd.h>
72
73 #include <security/audit/audit.h>
74 #include <security/mac/mac_framework.h>
75
76 #include <vm/vm.h>
77 #include <vm/vm_extern.h>
78 #include <vm/pmap.h>
79 #include <vm/vm_map.h>
80 #include <vm/vm_object.h>
81 #include <vm/vm_page.h>
82
83 static fo_rdwr_t vn_read;
84 static fo_rdwr_t vn_write;
85 static fo_rdwr_t vn_io_fault;
86 static fo_truncate_t vn_truncate;
87 static fo_ioctl_t vn_ioctl;
88 static fo_poll_t vn_poll;
89 static fo_kqfilter_t vn_kqfilter;
90 static fo_stat_t vn_statfile;
91 static fo_close_t vn_closefile;
92
93 struct fileops vnops = {
94 .fo_read = vn_io_fault,
95 .fo_write = vn_io_fault,
96 .fo_truncate = vn_truncate,
97 .fo_ioctl = vn_ioctl,
98 .fo_poll = vn_poll,
99 .fo_kqfilter = vn_kqfilter,
100 .fo_stat = vn_statfile,
101 .fo_close = vn_closefile,
102 .fo_chmod = vn_chmod,
103 .fo_chown = vn_chown,
104 .fo_sendfile = vn_sendfile,
105 .fo_seek = vn_seek,
106 .fo_flags = DFLAG_PASSABLE | DFLAG_SEEKABLE
107 };
108
109 static const int io_hold_cnt = 16;
110 static int vn_io_fault_enable = 1;
111 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_enable, CTLFLAG_RW,
112 &vn_io_fault_enable, 0, "Enable vn_io_fault lock avoidance");
113 static int vn_io_fault_prefault = 0;
114 SYSCTL_INT(_debug, OID_AUTO, vn_io_fault_prefault, CTLFLAG_RW,
115 &vn_io_fault_prefault, 0, "Enable vn_io_fault prefaulting");
116 static u_long vn_io_faults_cnt;
117 SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD,
118 &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers");
119
120 /*
121 * Returns true if vn_io_fault mode of handling the i/o request should
122 * be used.
123 */
124 static bool
125 do_vn_io_fault(struct vnode *vp, struct uio *uio)
126 {
127 struct mount *mp;
128
129 return (uio->uio_segflg == UIO_USERSPACE && vp->v_type == VREG &&
130 (mp = vp->v_mount) != NULL &&
131 (mp->mnt_kern_flag & MNTK_NO_IOPF) != 0 && vn_io_fault_enable);
132 }
133
134 /*
135 * Structure used to pass arguments to vn_io_fault1(), to do either
136 * file- or vnode-based I/O calls.
137 */
138 struct vn_io_fault_args {
139 enum {
140 VN_IO_FAULT_FOP,
141 VN_IO_FAULT_VOP
142 } kind;
143 struct ucred *cred;
144 int flags;
145 union {
146 struct fop_args_tag {
147 struct file *fp;
148 fo_rdwr_t *doio;
149 } fop_args;
150 struct vop_args_tag {
151 struct vnode *vp;
152 } vop_args;
153 } args;
154 };
155
156 static int vn_io_fault1(struct vnode *vp, struct uio *uio,
157 struct vn_io_fault_args *args, struct thread *td);
158
159 int
160 vn_open(ndp, flagp, cmode, fp)
161 struct nameidata *ndp;
162 int *flagp, cmode;
163 struct file *fp;
164 {
165 struct thread *td = ndp->ni_cnd.cn_thread;
166
167 return (vn_open_cred(ndp, flagp, cmode, 0, td->td_ucred, fp));
168 }
169
170 /*
171 * Common code for vnode open operations via a name lookup.
172 * Lookup the vnode and invoke VOP_CREATE if needed.
173 * Check permissions, and call the VOP_OPEN or VOP_CREATE routine.
174 *
175 * Note that this does NOT free nameidata for the successful case,
176 * due to the NDINIT being done elsewhere.
177 */
178 int
179 vn_open_cred(struct nameidata *ndp, int *flagp, int cmode, u_int vn_open_flags,
180 struct ucred *cred, struct file *fp)
181 {
182 struct vnode *vp;
183 struct mount *mp;
184 struct thread *td = ndp->ni_cnd.cn_thread;
185 struct vattr vat;
186 struct vattr *vap = &vat;
187 int fmode, error;
188
189 restart:
190 fmode = *flagp;
191 if ((fmode & (O_CREAT | O_EXCL | O_DIRECTORY)) == (O_CREAT |
192 O_EXCL | O_DIRECTORY))
193 return (EINVAL);
194 else if ((fmode & (O_CREAT | O_DIRECTORY)) == O_CREAT) {
195 ndp->ni_cnd.cn_nameiop = CREATE;
196 /*
197 * Set NOCACHE to avoid flushing the cache when
198 * rolling in many files at once.
199 */
200 ndp->ni_cnd.cn_flags = ISOPEN | LOCKPARENT | LOCKLEAF | NOCACHE;
201 if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
202 ndp->ni_cnd.cn_flags |= FOLLOW;
203 if (!(vn_open_flags & VN_OPEN_NOAUDIT))
204 ndp->ni_cnd.cn_flags |= AUDITVNODE1;
205 if (vn_open_flags & VN_OPEN_NOCAPCHECK)
206 ndp->ni_cnd.cn_flags |= NOCAPCHECK;
207 bwillwrite();
208 if ((error = namei(ndp)) != 0)
209 return (error);
210 if (ndp->ni_vp == NULL) {
211 VATTR_NULL(vap);
212 vap->va_type = VREG;
213 vap->va_mode = cmode;
214 if (fmode & O_EXCL)
215 vap->va_vaflags |= VA_EXCLUSIVE;
216 if (vn_start_write(ndp->ni_dvp, &mp, V_NOWAIT) != 0) {
217 NDFREE(ndp, NDF_ONLY_PNBUF);
218 vput(ndp->ni_dvp);
219 if ((error = vn_start_write(NULL, &mp,
220 V_XSLEEP | PCATCH)) != 0)
221 return (error);
222 goto restart;
223 }
224 if ((vn_open_flags & VN_OPEN_NAMECACHE) != 0)
225 ndp->ni_cnd.cn_flags |= MAKEENTRY;
226 #ifdef MAC
227 error = mac_vnode_check_create(cred, ndp->ni_dvp,
228 &ndp->ni_cnd, vap);
229 if (error == 0)
230 #endif
231 error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
232 &ndp->ni_cnd, vap);
233 vput(ndp->ni_dvp);
234 vn_finished_write(mp);
235 if (error) {
236 NDFREE(ndp, NDF_ONLY_PNBUF);
237 return (error);
238 }
239 fmode &= ~O_TRUNC;
240 vp = ndp->ni_vp;
241 } else {
242 if (ndp->ni_dvp == ndp->ni_vp)
243 vrele(ndp->ni_dvp);
244 else
245 vput(ndp->ni_dvp);
246 ndp->ni_dvp = NULL;
247 vp = ndp->ni_vp;
248 if (fmode & O_EXCL) {
249 error = EEXIST;
250 goto bad;
251 }
252 fmode &= ~O_CREAT;
253 }
254 } else {
255 ndp->ni_cnd.cn_nameiop = LOOKUP;
256 ndp->ni_cnd.cn_flags = ISOPEN |
257 ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF;
258 if (!(fmode & FWRITE))
259 ndp->ni_cnd.cn_flags |= LOCKSHARED;
260 if (!(vn_open_flags & VN_OPEN_NOAUDIT))
261 ndp->ni_cnd.cn_flags |= AUDITVNODE1;
262 if (vn_open_flags & VN_OPEN_NOCAPCHECK)
263 ndp->ni_cnd.cn_flags |= NOCAPCHECK;
264 if ((error = namei(ndp)) != 0)
265 return (error);
266 vp = ndp->ni_vp;
267 }
268 error = vn_open_vnode(vp, fmode, cred, td, fp);
269 if (error)
270 goto bad;
271 *flagp = fmode;
272 return (0);
273 bad:
274 NDFREE(ndp, NDF_ONLY_PNBUF);
275 vput(vp);
276 *flagp = fmode;
277 ndp->ni_vp = NULL;
278 return (error);
279 }
280
281 /*
282 * Common code for vnode open operations once a vnode is located.
283 * Check permissions, and call the VOP_OPEN routine.
284 */
285 int
286 vn_open_vnode(struct vnode *vp, int fmode, struct ucred *cred,
287 struct thread *td, struct file *fp)
288 {
289 struct mount *mp;
290 accmode_t accmode;
291 struct flock lf;
292 int error, have_flock, lock_flags, type;
293
294 if (vp->v_type == VLNK)
295 return (EMLINK);
296 if (vp->v_type == VSOCK)
297 return (EOPNOTSUPP);
298 if (vp->v_type != VDIR && fmode & O_DIRECTORY)
299 return (ENOTDIR);
300 accmode = 0;
301 if (fmode & (FWRITE | O_TRUNC)) {
302 if (vp->v_type == VDIR)
303 return (EISDIR);
304 accmode |= VWRITE;
305 }
306 if (fmode & FREAD)
307 accmode |= VREAD;
308 if (fmode & FEXEC)
309 accmode |= VEXEC;
310 if ((fmode & O_APPEND) && (fmode & FWRITE))
311 accmode |= VAPPEND;
312 #ifdef MAC
313 error = mac_vnode_check_open(cred, vp, accmode);
314 if (error)
315 return (error);
316 #endif
317 if ((fmode & O_CREAT) == 0) {
318 if (accmode & VWRITE) {
319 error = vn_writechk(vp);
320 if (error)
321 return (error);
322 }
323 if (accmode) {
324 error = VOP_ACCESS(vp, accmode, cred, td);
325 if (error)
326 return (error);
327 }
328 }
329 if (vp->v_type == VFIFO && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
330 vn_lock(vp, LK_UPGRADE | LK_RETRY);
331 if ((error = VOP_OPEN(vp, fmode, cred, td, fp)) != 0)
332 return (error);
333
334 if (fmode & (O_EXLOCK | O_SHLOCK)) {
335 KASSERT(fp != NULL, ("open with flock requires fp"));
336 lock_flags = VOP_ISLOCKED(vp);
337 VOP_UNLOCK(vp, 0);
338 lf.l_whence = SEEK_SET;
339 lf.l_start = 0;
340 lf.l_len = 0;
341 if (fmode & O_EXLOCK)
342 lf.l_type = F_WRLCK;
343 else
344 lf.l_type = F_RDLCK;
345 type = F_FLOCK;
346 if ((fmode & FNONBLOCK) == 0)
347 type |= F_WAIT;
348 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type);
349 have_flock = (error == 0);
350 vn_lock(vp, lock_flags | LK_RETRY);
351 if (error == 0 && vp->v_iflag & VI_DOOMED)
352 error = ENOENT;
353 /*
354 * Another thread might have used this vnode as an
355 * executable while the vnode lock was dropped.
356 * Ensure the vnode is still able to be opened for
357 * writing after the lock has been obtained.
358 */
359 if (error == 0 && accmode & VWRITE)
360 error = vn_writechk(vp);
361 if (error) {
362 VOP_UNLOCK(vp, 0);
363 if (have_flock) {
364 lf.l_whence = SEEK_SET;
365 lf.l_start = 0;
366 lf.l_len = 0;
367 lf.l_type = F_UNLCK;
368 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf,
369 F_FLOCK);
370 }
371 vn_start_write(vp, &mp, V_WAIT);
372 vn_lock(vp, lock_flags | LK_RETRY);
373 (void)VOP_CLOSE(vp, fmode, cred, td);
374 vn_finished_write(mp);
375 /* Prevent second close from fdrop()->vn_close(). */
376 if (fp != NULL)
377 fp->f_ops= &badfileops;
378 return (error);
379 }
380 fp->f_flag |= FHASLOCK;
381 }
382 if (fmode & FWRITE) {
383 VOP_ADD_WRITECOUNT(vp, 1);
384 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
385 __func__, vp, vp->v_writecount);
386 }
387 ASSERT_VOP_LOCKED(vp, "vn_open_vnode");
388 return (0);
389 }
390
391 /*
392 * Check for write permissions on the specified vnode.
393 * Prototype text segments cannot be written.
394 */
395 int
396 vn_writechk(vp)
397 register struct vnode *vp;
398 {
399
400 ASSERT_VOP_LOCKED(vp, "vn_writechk");
401 /*
402 * If there's shared text associated with
403 * the vnode, try to free it up once. If
404 * we fail, we can't allow writing.
405 */
406 if (VOP_IS_TEXT(vp))
407 return (ETXTBSY);
408
409 return (0);
410 }
411
412 /*
413 * Vnode close call
414 */
415 int
416 vn_close(vp, flags, file_cred, td)
417 register struct vnode *vp;
418 int flags;
419 struct ucred *file_cred;
420 struct thread *td;
421 {
422 struct mount *mp;
423 int error, lock_flags;
424
425 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 &&
426 MNT_EXTENDED_SHARED(vp->v_mount))
427 lock_flags = LK_SHARED;
428 else
429 lock_flags = LK_EXCLUSIVE;
430
431 vn_start_write(vp, &mp, V_WAIT);
432 vn_lock(vp, lock_flags | LK_RETRY);
433 if (flags & FWRITE) {
434 VNASSERT(vp->v_writecount > 0, vp,
435 ("vn_close: negative writecount"));
436 VOP_ADD_WRITECOUNT(vp, -1);
437 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
438 __func__, vp, vp->v_writecount);
439 }
440 error = VOP_CLOSE(vp, flags, file_cred, td);
441 vput(vp);
442 vn_finished_write(mp);
443 return (error);
444 }
445
446 /*
447 * Heuristic to detect sequential operation.
448 */
449 static int
450 sequential_heuristic(struct uio *uio, struct file *fp)
451 {
452
453 ASSERT_VOP_LOCKED(fp->f_vnode, __func__);
454 if (fp->f_flag & FRDAHEAD)
455 return (fp->f_seqcount << IO_SEQSHIFT);
456
457 /*
458 * Offset 0 is handled specially. open() sets f_seqcount to 1 so
459 * that the first I/O is normally considered to be slightly
460 * sequential. Seeking to offset 0 doesn't change sequentiality
461 * unless previous seeks have reduced f_seqcount to 0, in which
462 * case offset 0 is not special.
463 */
464 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
465 uio->uio_offset == fp->f_nextoff) {
466 /*
467 * f_seqcount is in units of fixed-size blocks so that it
468 * depends mainly on the amount of sequential I/O and not
469 * much on the number of sequential I/O's. The fixed size
470 * of 16384 is hard-coded here since it is (not quite) just
471 * a magic size that works well here. This size is more
472 * closely related to the best I/O size for real disks than
473 * to any block size used by software.
474 */
475 fp->f_seqcount += howmany(uio->uio_resid, 16384);
476 if (fp->f_seqcount > IO_SEQMAX)
477 fp->f_seqcount = IO_SEQMAX;
478 return (fp->f_seqcount << IO_SEQSHIFT);
479 }
480
481 /* Not sequential. Quickly draw-down sequentiality. */
482 if (fp->f_seqcount > 1)
483 fp->f_seqcount = 1;
484 else
485 fp->f_seqcount = 0;
486 return (0);
487 }
488
489 /*
490 * Package up an I/O request on a vnode into a uio and do it.
491 */
492 int
493 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset,
494 enum uio_seg segflg, int ioflg, struct ucred *active_cred,
495 struct ucred *file_cred, ssize_t *aresid, struct thread *td)
496 {
497 struct uio auio;
498 struct iovec aiov;
499 struct mount *mp;
500 struct ucred *cred;
501 void *rl_cookie;
502 struct vn_io_fault_args args;
503 int error, lock_flags;
504
505 auio.uio_iov = &aiov;
506 auio.uio_iovcnt = 1;
507 aiov.iov_base = base;
508 aiov.iov_len = len;
509 auio.uio_resid = len;
510 auio.uio_offset = offset;
511 auio.uio_segflg = segflg;
512 auio.uio_rw = rw;
513 auio.uio_td = td;
514 error = 0;
515
516 if ((ioflg & IO_NODELOCKED) == 0) {
517 if ((ioflg & IO_RANGELOCKED) == 0) {
518 if (rw == UIO_READ) {
519 rl_cookie = vn_rangelock_rlock(vp, offset,
520 offset + len);
521 } else {
522 rl_cookie = vn_rangelock_wlock(vp, offset,
523 offset + len);
524 }
525 } else
526 rl_cookie = NULL;
527 mp = NULL;
528 if (rw == UIO_WRITE) {
529 if (vp->v_type != VCHR &&
530 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
531 != 0)
532 goto out;
533 if (MNT_SHARED_WRITES(mp) ||
534 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount)))
535 lock_flags = LK_SHARED;
536 else
537 lock_flags = LK_EXCLUSIVE;
538 } else
539 lock_flags = LK_SHARED;
540 vn_lock(vp, lock_flags | LK_RETRY);
541 } else
542 rl_cookie = NULL;
543
544 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
545 #ifdef MAC
546 if ((ioflg & IO_NOMACCHECK) == 0) {
547 if (rw == UIO_READ)
548 error = mac_vnode_check_read(active_cred, file_cred,
549 vp);
550 else
551 error = mac_vnode_check_write(active_cred, file_cred,
552 vp);
553 }
554 #endif
555 if (error == 0) {
556 if (file_cred != NULL)
557 cred = file_cred;
558 else
559 cred = active_cred;
560 if (do_vn_io_fault(vp, &auio)) {
561 args.kind = VN_IO_FAULT_VOP;
562 args.cred = cred;
563 args.flags = ioflg;
564 args.args.vop_args.vp = vp;
565 error = vn_io_fault1(vp, &auio, &args, td);
566 } else if (rw == UIO_READ) {
567 error = VOP_READ(vp, &auio, ioflg, cred);
568 } else /* if (rw == UIO_WRITE) */ {
569 error = VOP_WRITE(vp, &auio, ioflg, cred);
570 }
571 }
572 if (aresid)
573 *aresid = auio.uio_resid;
574 else
575 if (auio.uio_resid && error == 0)
576 error = EIO;
577 if ((ioflg & IO_NODELOCKED) == 0) {
578 VOP_UNLOCK(vp, 0);
579 if (mp != NULL)
580 vn_finished_write(mp);
581 }
582 out:
583 if (rl_cookie != NULL)
584 vn_rangelock_unlock(vp, rl_cookie);
585 return (error);
586 }
587
588 /*
589 * Package up an I/O request on a vnode into a uio and do it. The I/O
590 * request is split up into smaller chunks and we try to avoid saturating
591 * the buffer cache while potentially holding a vnode locked, so we
592 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield()
593 * to give other processes a chance to lock the vnode (either other processes
594 * core'ing the same binary, or unrelated processes scanning the directory).
595 */
596 int
597 vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred,
598 file_cred, aresid, td)
599 enum uio_rw rw;
600 struct vnode *vp;
601 void *base;
602 size_t len;
603 off_t offset;
604 enum uio_seg segflg;
605 int ioflg;
606 struct ucred *active_cred;
607 struct ucred *file_cred;
608 size_t *aresid;
609 struct thread *td;
610 {
611 int error = 0;
612 ssize_t iaresid;
613
614 do {
615 int chunk;
616
617 /*
618 * Force `offset' to a multiple of MAXBSIZE except possibly
619 * for the first chunk, so that filesystems only need to
620 * write full blocks except possibly for the first and last
621 * chunks.
622 */
623 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE;
624
625 if (chunk > len)
626 chunk = len;
627 if (rw != UIO_READ && vp->v_type == VREG)
628 bwillwrite();
629 iaresid = 0;
630 error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
631 ioflg, active_cred, file_cred, &iaresid, td);
632 len -= chunk; /* aresid calc already includes length */
633 if (error)
634 break;
635 offset += chunk;
636 base = (char *)base + chunk;
637 kern_yield(PRI_USER);
638 } while (len);
639 if (aresid)
640 *aresid = len + iaresid;
641 return (error);
642 }
643
644 off_t
645 foffset_lock(struct file *fp, int flags)
646 {
647 struct mtx *mtxp;
648 off_t res;
649
650 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
651
652 #if OFF_MAX <= LONG_MAX
653 /*
654 * Caller only wants the current f_offset value. Assume that
655 * the long and shorter integer types reads are atomic.
656 */
657 if ((flags & FOF_NOLOCK) != 0)
658 return (fp->f_offset);
659 #endif
660
661 /*
662 * According to McKusick the vn lock was protecting f_offset here.
663 * It is now protected by the FOFFSET_LOCKED flag.
664 */
665 mtxp = mtx_pool_find(mtxpool_sleep, fp);
666 mtx_lock(mtxp);
667 if ((flags & FOF_NOLOCK) == 0) {
668 while (fp->f_vnread_flags & FOFFSET_LOCKED) {
669 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING;
670 msleep(&fp->f_vnread_flags, mtxp, PUSER -1,
671 "vofflock", 0);
672 }
673 fp->f_vnread_flags |= FOFFSET_LOCKED;
674 }
675 res = fp->f_offset;
676 mtx_unlock(mtxp);
677 return (res);
678 }
679
680 void
681 foffset_unlock(struct file *fp, off_t val, int flags)
682 {
683 struct mtx *mtxp;
684
685 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
686
687 #if OFF_MAX <= LONG_MAX
688 if ((flags & FOF_NOLOCK) != 0) {
689 if ((flags & FOF_NOUPDATE) == 0)
690 fp->f_offset = val;
691 if ((flags & FOF_NEXTOFF) != 0)
692 fp->f_nextoff = val;
693 return;
694 }
695 #endif
696
697 mtxp = mtx_pool_find(mtxpool_sleep, fp);
698 mtx_lock(mtxp);
699 if ((flags & FOF_NOUPDATE) == 0)
700 fp->f_offset = val;
701 if ((flags & FOF_NEXTOFF) != 0)
702 fp->f_nextoff = val;
703 if ((flags & FOF_NOLOCK) == 0) {
704 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0,
705 ("Lost FOFFSET_LOCKED"));
706 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING)
707 wakeup(&fp->f_vnread_flags);
708 fp->f_vnread_flags = 0;
709 }
710 mtx_unlock(mtxp);
711 }
712
713 void
714 foffset_lock_uio(struct file *fp, struct uio *uio, int flags)
715 {
716
717 if ((flags & FOF_OFFSET) == 0)
718 uio->uio_offset = foffset_lock(fp, flags);
719 }
720
721 void
722 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags)
723 {
724
725 if ((flags & FOF_OFFSET) == 0)
726 foffset_unlock(fp, uio->uio_offset, flags);
727 }
728
729 static int
730 get_advice(struct file *fp, struct uio *uio)
731 {
732 struct mtx *mtxp;
733 int ret;
734
735 ret = POSIX_FADV_NORMAL;
736 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG)
737 return (ret);
738
739 mtxp = mtx_pool_find(mtxpool_sleep, fp);
740 mtx_lock(mtxp);
741 if (fp->f_advice != NULL &&
742 uio->uio_offset >= fp->f_advice->fa_start &&
743 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end)
744 ret = fp->f_advice->fa_advice;
745 mtx_unlock(mtxp);
746 return (ret);
747 }
748
749 /*
750 * File table vnode read routine.
751 */
752 static int
753 vn_read(fp, uio, active_cred, flags, td)
754 struct file *fp;
755 struct uio *uio;
756 struct ucred *active_cred;
757 int flags;
758 struct thread *td;
759 {
760 struct vnode *vp;
761 struct mtx *mtxp;
762 int error, ioflag;
763 int advice;
764 off_t offset, start, end;
765
766 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
767 uio->uio_td, td));
768 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
769 vp = fp->f_vnode;
770 ioflag = 0;
771 if (fp->f_flag & FNONBLOCK)
772 ioflag |= IO_NDELAY;
773 if (fp->f_flag & O_DIRECT)
774 ioflag |= IO_DIRECT;
775 advice = get_advice(fp, uio);
776 vn_lock(vp, LK_SHARED | LK_RETRY);
777
778 switch (advice) {
779 case POSIX_FADV_NORMAL:
780 case POSIX_FADV_SEQUENTIAL:
781 case POSIX_FADV_NOREUSE:
782 ioflag |= sequential_heuristic(uio, fp);
783 break;
784 case POSIX_FADV_RANDOM:
785 /* Disable read-ahead for random I/O. */
786 break;
787 }
788 offset = uio->uio_offset;
789
790 #ifdef MAC
791 error = mac_vnode_check_read(active_cred, fp->f_cred, vp);
792 if (error == 0)
793 #endif
794 error = VOP_READ(vp, uio, ioflag, fp->f_cred);
795 fp->f_nextoff = uio->uio_offset;
796 VOP_UNLOCK(vp, 0);
797 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
798 offset != uio->uio_offset) {
799 /*
800 * Use POSIX_FADV_DONTNEED to flush clean pages and
801 * buffers for the backing file after a
802 * POSIX_FADV_NOREUSE read(2). To optimize the common
803 * case of using POSIX_FADV_NOREUSE with sequential
804 * access, track the previous implicit DONTNEED
805 * request and grow this request to include the
806 * current read(2) in addition to the previous
807 * DONTNEED. With purely sequential access this will
808 * cause the DONTNEED requests to continously grow to
809 * cover all of the previously read regions of the
810 * file. This allows filesystem blocks that are
811 * accessed by multiple calls to read(2) to be flushed
812 * once the last read(2) finishes.
813 */
814 start = offset;
815 end = uio->uio_offset - 1;
816 mtxp = mtx_pool_find(mtxpool_sleep, fp);
817 mtx_lock(mtxp);
818 if (fp->f_advice != NULL &&
819 fp->f_advice->fa_advice == POSIX_FADV_NOREUSE) {
820 if (start != 0 && fp->f_advice->fa_prevend + 1 == start)
821 start = fp->f_advice->fa_prevstart;
822 else if (fp->f_advice->fa_prevstart != 0 &&
823 fp->f_advice->fa_prevstart == end + 1)
824 end = fp->f_advice->fa_prevend;
825 fp->f_advice->fa_prevstart = start;
826 fp->f_advice->fa_prevend = end;
827 }
828 mtx_unlock(mtxp);
829 error = VOP_ADVISE(vp, start, end, POSIX_FADV_DONTNEED);
830 }
831 return (error);
832 }
833
834 /*
835 * File table vnode write routine.
836 */
837 static int
838 vn_write(fp, uio, active_cred, flags, td)
839 struct file *fp;
840 struct uio *uio;
841 struct ucred *active_cred;
842 int flags;
843 struct thread *td;
844 {
845 struct vnode *vp;
846 struct mount *mp;
847 struct mtx *mtxp;
848 int error, ioflag, lock_flags;
849 int advice;
850 off_t offset, start, end;
851
852 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
853 uio->uio_td, td));
854 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
855 vp = fp->f_vnode;
856 if (vp->v_type == VREG)
857 bwillwrite();
858 ioflag = IO_UNIT;
859 if (vp->v_type == VREG && (fp->f_flag & O_APPEND))
860 ioflag |= IO_APPEND;
861 if (fp->f_flag & FNONBLOCK)
862 ioflag |= IO_NDELAY;
863 if (fp->f_flag & O_DIRECT)
864 ioflag |= IO_DIRECT;
865 if ((fp->f_flag & O_FSYNC) ||
866 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS)))
867 ioflag |= IO_SYNC;
868 mp = NULL;
869 if (vp->v_type != VCHR &&
870 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
871 goto unlock;
872
873 advice = get_advice(fp, uio);
874
875 if (MNT_SHARED_WRITES(mp) ||
876 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) {
877 lock_flags = LK_SHARED;
878 } else {
879 lock_flags = LK_EXCLUSIVE;
880 }
881
882 vn_lock(vp, lock_flags | LK_RETRY);
883 switch (advice) {
884 case POSIX_FADV_NORMAL:
885 case POSIX_FADV_SEQUENTIAL:
886 case POSIX_FADV_NOREUSE:
887 ioflag |= sequential_heuristic(uio, fp);
888 break;
889 case POSIX_FADV_RANDOM:
890 /* XXX: Is this correct? */
891 break;
892 }
893 offset = uio->uio_offset;
894
895 #ifdef MAC
896 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
897 if (error == 0)
898 #endif
899 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred);
900 fp->f_nextoff = uio->uio_offset;
901 VOP_UNLOCK(vp, 0);
902 if (vp->v_type != VCHR)
903 vn_finished_write(mp);
904 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
905 offset != uio->uio_offset) {
906 /*
907 * Use POSIX_FADV_DONTNEED to flush clean pages and
908 * buffers for the backing file after a
909 * POSIX_FADV_NOREUSE write(2). To optimize the
910 * common case of using POSIX_FADV_NOREUSE with
911 * sequential access, track the previous implicit
912 * DONTNEED request and grow this request to include
913 * the current write(2) in addition to the previous
914 * DONTNEED. With purely sequential access this will
915 * cause the DONTNEED requests to continously grow to
916 * cover all of the previously written regions of the
917 * file.
918 *
919 * Note that the blocks just written are almost
920 * certainly still dirty, so this only works when
921 * VOP_ADVISE() calls from subsequent writes push out
922 * the data written by this write(2) once the backing
923 * buffers are clean. However, as compared to forcing
924 * IO_DIRECT, this gives much saner behavior. Write
925 * clustering is still allowed, and clean pages are
926 * merely moved to the cache page queue rather than
927 * outright thrown away. This means a subsequent
928 * read(2) can still avoid hitting the disk if the
929 * pages have not been reclaimed.
930 *
931 * This does make POSIX_FADV_NOREUSE largely useless
932 * with non-sequential access. However, sequential
933 * access is the more common use case and the flag is
934 * merely advisory.
935 */
936 start = offset;
937 end = uio->uio_offset - 1;
938 mtxp = mtx_pool_find(mtxpool_sleep, fp);
939 mtx_lock(mtxp);
940 if (fp->f_advice != NULL &&
941 fp->f_advice->fa_advice == POSIX_FADV_NOREUSE) {
942 if (start != 0 && fp->f_advice->fa_prevend + 1 == start)
943 start = fp->f_advice->fa_prevstart;
944 else if (fp->f_advice->fa_prevstart != 0 &&
945 fp->f_advice->fa_prevstart == end + 1)
946 end = fp->f_advice->fa_prevend;
947 fp->f_advice->fa_prevstart = start;
948 fp->f_advice->fa_prevend = end;
949 }
950 mtx_unlock(mtxp);
951 error = VOP_ADVISE(vp, start, end, POSIX_FADV_DONTNEED);
952 }
953
954 unlock:
955 return (error);
956 }
957
958 /*
959 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to
960 * prevent the following deadlock:
961 *
962 * Assume that the thread A reads from the vnode vp1 into userspace
963 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is
964 * currently not resident, then system ends up with the call chain
965 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] ->
966 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2)
967 * which establishes lock order vp1->vn_lock, then vp2->vn_lock.
968 * If, at the same time, thread B reads from vnode vp2 into buffer buf2
969 * backed by the pages of vnode vp1, and some page in buf2 is not
970 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock.
971 *
972 * To prevent the lock order reversal and deadlock, vn_io_fault() does
973 * not allow page faults to happen during VOP_READ() or VOP_WRITE().
974 * Instead, it first tries to do the whole range i/o with pagefaults
975 * disabled. If all pages in the i/o buffer are resident and mapped,
976 * VOP will succeed (ignoring the genuine filesystem errors).
977 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do
978 * i/o in chunks, with all pages in the chunk prefaulted and held
979 * using vm_fault_quick_hold_pages().
980 *
981 * Filesystems using this deadlock avoidance scheme should use the
982 * array of the held pages from uio, saved in the curthread->td_ma,
983 * instead of doing uiomove(). A helper function
984 * vn_io_fault_uiomove() converts uiomove request into
985 * uiomove_fromphys() over td_ma array.
986 *
987 * Since vnode locks do not cover the whole i/o anymore, rangelocks
988 * make the current i/o request atomic with respect to other i/os and
989 * truncations.
990 */
991
992 /*
993 * Decode vn_io_fault_args and perform the corresponding i/o.
994 */
995 static int
996 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio,
997 struct thread *td)
998 {
999
1000 switch (args->kind) {
1001 case VN_IO_FAULT_FOP:
1002 return ((args->args.fop_args.doio)(args->args.fop_args.fp,
1003 uio, args->cred, args->flags, td));
1004 case VN_IO_FAULT_VOP:
1005 if (uio->uio_rw == UIO_READ) {
1006 return (VOP_READ(args->args.vop_args.vp, uio,
1007 args->flags, args->cred));
1008 } else if (uio->uio_rw == UIO_WRITE) {
1009 return (VOP_WRITE(args->args.vop_args.vp, uio,
1010 args->flags, args->cred));
1011 }
1012 break;
1013 }
1014 panic("vn_io_fault_doio: unknown kind of io %d %d", args->kind,
1015 uio->uio_rw);
1016 }
1017
1018 static int
1019 vn_io_fault_touch(char *base, const struct uio *uio)
1020 {
1021 int r;
1022
1023 r = fubyte(base);
1024 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1))
1025 return (EFAULT);
1026 return (0);
1027 }
1028
1029 static int
1030 vn_io_fault_prefault_user(const struct uio *uio)
1031 {
1032 char *base;
1033 const struct iovec *iov;
1034 size_t len;
1035 ssize_t resid;
1036 int error, i;
1037
1038 KASSERT(uio->uio_segflg == UIO_USERSPACE,
1039 ("vn_io_fault_prefault userspace"));
1040
1041 error = i = 0;
1042 iov = uio->uio_iov;
1043 resid = uio->uio_resid;
1044 base = iov->iov_base;
1045 len = iov->iov_len;
1046 while (resid > 0) {
1047 error = vn_io_fault_touch(base, uio);
1048 if (error != 0)
1049 break;
1050 if (len < PAGE_SIZE) {
1051 if (len != 0) {
1052 error = vn_io_fault_touch(base + len - 1, uio);
1053 if (error != 0)
1054 break;
1055 resid -= len;
1056 }
1057 if (++i >= uio->uio_iovcnt)
1058 break;
1059 iov = uio->uio_iov + i;
1060 base = iov->iov_base;
1061 len = iov->iov_len;
1062 } else {
1063 len -= PAGE_SIZE;
1064 base += PAGE_SIZE;
1065 resid -= PAGE_SIZE;
1066 }
1067 }
1068 return (error);
1069 }
1070
1071 /*
1072 * Common code for vn_io_fault(), agnostic to the kind of i/o request.
1073 * Uses vn_io_fault_doio() to make the call to an actual i/o function.
1074 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request
1075 * into args and call vn_io_fault1() to handle faults during the user
1076 * mode buffer accesses.
1077 */
1078 static int
1079 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args,
1080 struct thread *td)
1081 {
1082 vm_page_t ma[io_hold_cnt + 2];
1083 struct uio *uio_clone, short_uio;
1084 struct iovec short_iovec[1];
1085 vm_page_t *prev_td_ma;
1086 vm_prot_t prot;
1087 vm_offset_t addr, end;
1088 size_t len, resid;
1089 ssize_t adv;
1090 int error, cnt, save, saveheld, prev_td_ma_cnt;
1091
1092 if (vn_io_fault_prefault) {
1093 error = vn_io_fault_prefault_user(uio);
1094 if (error != 0)
1095 return (error); /* Or ignore ? */
1096 }
1097
1098 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ;
1099
1100 /*
1101 * The UFS follows IO_UNIT directive and replays back both
1102 * uio_offset and uio_resid if an error is encountered during the
1103 * operation. But, since the iovec may be already advanced,
1104 * uio is still in an inconsistent state.
1105 *
1106 * Cache a copy of the original uio, which is advanced to the redo
1107 * point using UIO_NOCOPY below.
1108 */
1109 uio_clone = cloneuio(uio);
1110 resid = uio->uio_resid;
1111
1112 short_uio.uio_segflg = UIO_USERSPACE;
1113 short_uio.uio_rw = uio->uio_rw;
1114 short_uio.uio_td = uio->uio_td;
1115
1116 save = vm_fault_disable_pagefaults();
1117 error = vn_io_fault_doio(args, uio, td);
1118 if (error != EFAULT)
1119 goto out;
1120
1121 atomic_add_long(&vn_io_faults_cnt, 1);
1122 uio_clone->uio_segflg = UIO_NOCOPY;
1123 uiomove(NULL, resid - uio->uio_resid, uio_clone);
1124 uio_clone->uio_segflg = uio->uio_segflg;
1125
1126 saveheld = curthread_pflags_set(TDP_UIOHELD);
1127 prev_td_ma = td->td_ma;
1128 prev_td_ma_cnt = td->td_ma_cnt;
1129
1130 while (uio_clone->uio_resid != 0) {
1131 len = uio_clone->uio_iov->iov_len;
1132 if (len == 0) {
1133 KASSERT(uio_clone->uio_iovcnt >= 1,
1134 ("iovcnt underflow"));
1135 uio_clone->uio_iov++;
1136 uio_clone->uio_iovcnt--;
1137 continue;
1138 }
1139 if (len > io_hold_cnt * PAGE_SIZE)
1140 len = io_hold_cnt * PAGE_SIZE;
1141 addr = (uintptr_t)uio_clone->uio_iov->iov_base;
1142 end = round_page(addr + len);
1143 if (end < addr) {
1144 error = EFAULT;
1145 break;
1146 }
1147 cnt = atop(end - trunc_page(addr));
1148 /*
1149 * A perfectly misaligned address and length could cause
1150 * both the start and the end of the chunk to use partial
1151 * page. +2 accounts for such a situation.
1152 */
1153 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map,
1154 addr, len, prot, ma, io_hold_cnt + 2);
1155 if (cnt == -1) {
1156 error = EFAULT;
1157 break;
1158 }
1159 short_uio.uio_iov = &short_iovec[0];
1160 short_iovec[0].iov_base = (void *)addr;
1161 short_uio.uio_iovcnt = 1;
1162 short_uio.uio_resid = short_iovec[0].iov_len = len;
1163 short_uio.uio_offset = uio_clone->uio_offset;
1164 td->td_ma = ma;
1165 td->td_ma_cnt = cnt;
1166
1167 error = vn_io_fault_doio(args, &short_uio, td);
1168 vm_page_unhold_pages(ma, cnt);
1169 adv = len - short_uio.uio_resid;
1170
1171 uio_clone->uio_iov->iov_base =
1172 (char *)uio_clone->uio_iov->iov_base + adv;
1173 uio_clone->uio_iov->iov_len -= adv;
1174 uio_clone->uio_resid -= adv;
1175 uio_clone->uio_offset += adv;
1176
1177 uio->uio_resid -= adv;
1178 uio->uio_offset += adv;
1179
1180 if (error != 0 || adv == 0)
1181 break;
1182 }
1183 td->td_ma = prev_td_ma;
1184 td->td_ma_cnt = prev_td_ma_cnt;
1185 curthread_pflags_restore(saveheld);
1186 out:
1187 vm_fault_enable_pagefaults(save);
1188 free(uio_clone, M_IOV);
1189 return (error);
1190 }
1191
1192 static int
1193 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred,
1194 int flags, struct thread *td)
1195 {
1196 fo_rdwr_t *doio;
1197 struct vnode *vp;
1198 void *rl_cookie;
1199 struct vn_io_fault_args args;
1200 int error;
1201
1202 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write;
1203 vp = fp->f_vnode;
1204 foffset_lock_uio(fp, uio, flags);
1205 if (do_vn_io_fault(vp, uio)) {
1206 args.kind = VN_IO_FAULT_FOP;
1207 args.args.fop_args.fp = fp;
1208 args.args.fop_args.doio = doio;
1209 args.cred = active_cred;
1210 args.flags = flags | FOF_OFFSET;
1211 if (uio->uio_rw == UIO_READ) {
1212 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset,
1213 uio->uio_offset + uio->uio_resid);
1214 } else if ((fp->f_flag & O_APPEND) != 0 ||
1215 (flags & FOF_OFFSET) == 0) {
1216 /* For appenders, punt and lock the whole range. */
1217 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1218 } else {
1219 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset,
1220 uio->uio_offset + uio->uio_resid);
1221 }
1222 error = vn_io_fault1(vp, uio, &args, td);
1223 vn_rangelock_unlock(vp, rl_cookie);
1224 } else {
1225 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td);
1226 }
1227 foffset_unlock_uio(fp, uio, flags);
1228 return (error);
1229 }
1230
1231 /*
1232 * Helper function to perform the requested uiomove operation using
1233 * the held pages for io->uio_iov[0].iov_base buffer instead of
1234 * copyin/copyout. Access to the pages with uiomove_fromphys()
1235 * instead of iov_base prevents page faults that could occur due to
1236 * pmap_collect() invalidating the mapping created by
1237 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or
1238 * object cleanup revoking the write access from page mappings.
1239 *
1240 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove()
1241 * instead of plain uiomove().
1242 */
1243 int
1244 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio)
1245 {
1246 struct uio transp_uio;
1247 struct iovec transp_iov[1];
1248 struct thread *td;
1249 size_t adv;
1250 int error, pgadv;
1251
1252 td = curthread;
1253 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1254 uio->uio_segflg != UIO_USERSPACE)
1255 return (uiomove(data, xfersize, uio));
1256
1257 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1258 transp_iov[0].iov_base = data;
1259 transp_uio.uio_iov = &transp_iov[0];
1260 transp_uio.uio_iovcnt = 1;
1261 if (xfersize > uio->uio_resid)
1262 xfersize = uio->uio_resid;
1263 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize;
1264 transp_uio.uio_offset = 0;
1265 transp_uio.uio_segflg = UIO_SYSSPACE;
1266 /*
1267 * Since transp_iov points to data, and td_ma page array
1268 * corresponds to original uio->uio_iov, we need to invert the
1269 * direction of the i/o operation as passed to
1270 * uiomove_fromphys().
1271 */
1272 switch (uio->uio_rw) {
1273 case UIO_WRITE:
1274 transp_uio.uio_rw = UIO_READ;
1275 break;
1276 case UIO_READ:
1277 transp_uio.uio_rw = UIO_WRITE;
1278 break;
1279 }
1280 transp_uio.uio_td = uio->uio_td;
1281 error = uiomove_fromphys(td->td_ma,
1282 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK,
1283 xfersize, &transp_uio);
1284 adv = xfersize - transp_uio.uio_resid;
1285 pgadv =
1286 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) -
1287 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT);
1288 td->td_ma += pgadv;
1289 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1290 pgadv));
1291 td->td_ma_cnt -= pgadv;
1292 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv;
1293 uio->uio_iov->iov_len -= adv;
1294 uio->uio_resid -= adv;
1295 uio->uio_offset += adv;
1296 return (error);
1297 }
1298
1299 int
1300 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize,
1301 struct uio *uio)
1302 {
1303 struct thread *td;
1304 vm_offset_t iov_base;
1305 int cnt, pgadv;
1306
1307 td = curthread;
1308 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1309 uio->uio_segflg != UIO_USERSPACE)
1310 return (uiomove_fromphys(ma, offset, xfersize, uio));
1311
1312 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1313 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize;
1314 iov_base = (vm_offset_t)uio->uio_iov->iov_base;
1315 switch (uio->uio_rw) {
1316 case UIO_WRITE:
1317 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma,
1318 offset, cnt);
1319 break;
1320 case UIO_READ:
1321 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK,
1322 cnt);
1323 break;
1324 }
1325 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT);
1326 td->td_ma += pgadv;
1327 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1328 pgadv));
1329 td->td_ma_cnt -= pgadv;
1330 uio->uio_iov->iov_base = (char *)(iov_base + cnt);
1331 uio->uio_iov->iov_len -= cnt;
1332 uio->uio_resid -= cnt;
1333 uio->uio_offset += cnt;
1334 return (0);
1335 }
1336
1337
1338 /*
1339 * File table truncate routine.
1340 */
1341 static int
1342 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred,
1343 struct thread *td)
1344 {
1345 struct vattr vattr;
1346 struct mount *mp;
1347 struct vnode *vp;
1348 void *rl_cookie;
1349 int error;
1350
1351 vp = fp->f_vnode;
1352
1353 /*
1354 * Lock the whole range for truncation. Otherwise split i/o
1355 * might happen partly before and partly after the truncation.
1356 */
1357 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1358 error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
1359 if (error)
1360 goto out1;
1361 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1362 if (vp->v_type == VDIR) {
1363 error = EISDIR;
1364 goto out;
1365 }
1366 #ifdef MAC
1367 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
1368 if (error)
1369 goto out;
1370 #endif
1371 error = vn_writechk(vp);
1372 if (error == 0) {
1373 VATTR_NULL(&vattr);
1374 vattr.va_size = length;
1375 error = VOP_SETATTR(vp, &vattr, fp->f_cred);
1376 }
1377 out:
1378 VOP_UNLOCK(vp, 0);
1379 vn_finished_write(mp);
1380 out1:
1381 vn_rangelock_unlock(vp, rl_cookie);
1382 return (error);
1383 }
1384
1385 /*
1386 * File table vnode stat routine.
1387 */
1388 static int
1389 vn_statfile(fp, sb, active_cred, td)
1390 struct file *fp;
1391 struct stat *sb;
1392 struct ucred *active_cred;
1393 struct thread *td;
1394 {
1395 struct vnode *vp = fp->f_vnode;
1396 int error;
1397
1398 vn_lock(vp, LK_SHARED | LK_RETRY);
1399 error = vn_stat(vp, sb, active_cred, fp->f_cred, td);
1400 VOP_UNLOCK(vp, 0);
1401
1402 return (error);
1403 }
1404
1405 /*
1406 * Stat a vnode; implementation for the stat syscall
1407 */
1408 int
1409 vn_stat(vp, sb, active_cred, file_cred, td)
1410 struct vnode *vp;
1411 register struct stat *sb;
1412 struct ucred *active_cred;
1413 struct ucred *file_cred;
1414 struct thread *td;
1415 {
1416 struct vattr vattr;
1417 register struct vattr *vap;
1418 int error;
1419 u_short mode;
1420
1421 #ifdef MAC
1422 error = mac_vnode_check_stat(active_cred, file_cred, vp);
1423 if (error)
1424 return (error);
1425 #endif
1426
1427 vap = &vattr;
1428
1429 /*
1430 * Initialize defaults for new and unusual fields, so that file
1431 * systems which don't support these fields don't need to know
1432 * about them.
1433 */
1434 vap->va_birthtime.tv_sec = -1;
1435 vap->va_birthtime.tv_nsec = 0;
1436 vap->va_fsid = VNOVAL;
1437 vap->va_rdev = NODEV;
1438
1439 error = VOP_GETATTR(vp, vap, active_cred);
1440 if (error)
1441 return (error);
1442
1443 /*
1444 * Zero the spare stat fields
1445 */
1446 bzero(sb, sizeof *sb);
1447
1448 /*
1449 * Copy from vattr table
1450 */
1451 if (vap->va_fsid != VNOVAL)
1452 sb->st_dev = vap->va_fsid;
1453 else
1454 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
1455 sb->st_ino = vap->va_fileid;
1456 mode = vap->va_mode;
1457 switch (vap->va_type) {
1458 case VREG:
1459 mode |= S_IFREG;
1460 break;
1461 case VDIR:
1462 mode |= S_IFDIR;
1463 break;
1464 case VBLK:
1465 mode |= S_IFBLK;
1466 break;
1467 case VCHR:
1468 mode |= S_IFCHR;
1469 break;
1470 case VLNK:
1471 mode |= S_IFLNK;
1472 break;
1473 case VSOCK:
1474 mode |= S_IFSOCK;
1475 break;
1476 case VFIFO:
1477 mode |= S_IFIFO;
1478 break;
1479 default:
1480 return (EBADF);
1481 };
1482 sb->st_mode = mode;
1483 sb->st_nlink = vap->va_nlink;
1484 sb->st_uid = vap->va_uid;
1485 sb->st_gid = vap->va_gid;
1486 sb->st_rdev = vap->va_rdev;
1487 if (vap->va_size > OFF_MAX)
1488 return (EOVERFLOW);
1489 sb->st_size = vap->va_size;
1490 sb->st_atim = vap->va_atime;
1491 sb->st_mtim = vap->va_mtime;
1492 sb->st_ctim = vap->va_ctime;
1493 sb->st_birthtim = vap->va_birthtime;
1494
1495 /*
1496 * According to www.opengroup.org, the meaning of st_blksize is
1497 * "a filesystem-specific preferred I/O block size for this
1498 * object. In some filesystem types, this may vary from file
1499 * to file"
1500 * Use miminum/default of PAGE_SIZE (e.g. for VCHR).
1501 */
1502
1503 sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize);
1504
1505 sb->st_flags = vap->va_flags;
1506 if (priv_check(td, PRIV_VFS_GENERATION))
1507 sb->st_gen = 0;
1508 else
1509 sb->st_gen = vap->va_gen;
1510
1511 sb->st_blocks = vap->va_bytes / S_BLKSIZE;
1512 return (0);
1513 }
1514
1515 /*
1516 * File table vnode ioctl routine.
1517 */
1518 static int
1519 vn_ioctl(fp, com, data, active_cred, td)
1520 struct file *fp;
1521 u_long com;
1522 void *data;
1523 struct ucred *active_cred;
1524 struct thread *td;
1525 {
1526 struct vattr vattr;
1527 struct vnode *vp;
1528 int error;
1529
1530 vp = fp->f_vnode;
1531 switch (vp->v_type) {
1532 case VDIR:
1533 case VREG:
1534 switch (com) {
1535 case FIONREAD:
1536 vn_lock(vp, LK_SHARED | LK_RETRY);
1537 error = VOP_GETATTR(vp, &vattr, active_cred);
1538 VOP_UNLOCK(vp, 0);
1539 if (error == 0)
1540 *(int *)data = vattr.va_size - fp->f_offset;
1541 return (error);
1542 case FIONBIO:
1543 case FIOASYNC:
1544 return (0);
1545 default:
1546 return (VOP_IOCTL(vp, com, data, fp->f_flag,
1547 active_cred, td));
1548 }
1549 default:
1550 return (ENOTTY);
1551 }
1552 }
1553
1554 /*
1555 * File table vnode poll routine.
1556 */
1557 static int
1558 vn_poll(fp, events, active_cred, td)
1559 struct file *fp;
1560 int events;
1561 struct ucred *active_cred;
1562 struct thread *td;
1563 {
1564 struct vnode *vp;
1565 int error;
1566
1567 vp = fp->f_vnode;
1568 #ifdef MAC
1569 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1570 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp);
1571 VOP_UNLOCK(vp, 0);
1572 if (!error)
1573 #endif
1574
1575 error = VOP_POLL(vp, events, fp->f_cred, td);
1576 return (error);
1577 }
1578
1579 /*
1580 * Acquire the requested lock and then check for validity. LK_RETRY
1581 * permits vn_lock to return doomed vnodes.
1582 */
1583 int
1584 _vn_lock(struct vnode *vp, int flags, char *file, int line)
1585 {
1586 int error;
1587
1588 VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
1589 ("vn_lock called with no locktype."));
1590 do {
1591 #ifdef DEBUG_VFS_LOCKS
1592 KASSERT(vp->v_holdcnt != 0,
1593 ("vn_lock %p: zero hold count", vp));
1594 #endif
1595 error = VOP_LOCK1(vp, flags, file, line);
1596 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */
1597 KASSERT((flags & LK_RETRY) == 0 || error == 0,
1598 ("LK_RETRY set with incompatible flags (0x%x) or an error occured (%d)",
1599 flags, error));
1600 /*
1601 * Callers specify LK_RETRY if they wish to get dead vnodes.
1602 * If RETRY is not set, we return ENOENT instead.
1603 */
1604 if (error == 0 && vp->v_iflag & VI_DOOMED &&
1605 (flags & LK_RETRY) == 0) {
1606 VOP_UNLOCK(vp, 0);
1607 error = ENOENT;
1608 break;
1609 }
1610 } while (flags & LK_RETRY && error != 0);
1611 return (error);
1612 }
1613
1614 /*
1615 * File table vnode close routine.
1616 */
1617 static int
1618 vn_closefile(fp, td)
1619 struct file *fp;
1620 struct thread *td;
1621 {
1622 struct vnode *vp;
1623 struct flock lf;
1624 int error;
1625
1626 vp = fp->f_vnode;
1627 fp->f_ops = &badfileops;
1628
1629 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK)
1630 vref(vp);
1631
1632 error = vn_close(vp, fp->f_flag, fp->f_cred, td);
1633
1634 if (fp->f_type == DTYPE_VNODE && fp->f_flag & FHASLOCK) {
1635 lf.l_whence = SEEK_SET;
1636 lf.l_start = 0;
1637 lf.l_len = 0;
1638 lf.l_type = F_UNLCK;
1639 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK);
1640 vrele(vp);
1641 }
1642 return (error);
1643 }
1644
1645 /*
1646 * Preparing to start a filesystem write operation. If the operation is
1647 * permitted, then we bump the count of operations in progress and
1648 * proceed. If a suspend request is in progress, we wait until the
1649 * suspension is over, and then proceed.
1650 */
1651 static int
1652 vn_start_write_locked(struct mount *mp, int flags)
1653 {
1654 int error, mflags;
1655
1656 mtx_assert(MNT_MTX(mp), MA_OWNED);
1657 error = 0;
1658
1659 /*
1660 * Check on status of suspension.
1661 */
1662 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 ||
1663 mp->mnt_susp_owner != curthread) {
1664 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ?
1665 (flags & PCATCH) : 0) | (PUSER - 1);
1666 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1667 if (flags & V_NOWAIT) {
1668 error = EWOULDBLOCK;
1669 goto unlock;
1670 }
1671 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags,
1672 "suspfs", 0);
1673 if (error)
1674 goto unlock;
1675 }
1676 }
1677 if (flags & V_XSLEEP)
1678 goto unlock;
1679 mp->mnt_writeopcount++;
1680 unlock:
1681 if (error != 0 || (flags & V_XSLEEP) != 0)
1682 MNT_REL(mp);
1683 MNT_IUNLOCK(mp);
1684 return (error);
1685 }
1686
1687 int
1688 vn_start_write(struct vnode *vp, struct mount **mpp, int flags)
1689 {
1690 struct mount *mp;
1691 int error;
1692
1693 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1694 ("V_MNTREF requires mp"));
1695
1696 error = 0;
1697 /*
1698 * If a vnode is provided, get and return the mount point that
1699 * to which it will write.
1700 */
1701 if (vp != NULL) {
1702 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1703 *mpp = NULL;
1704 if (error != EOPNOTSUPP)
1705 return (error);
1706 return (0);
1707 }
1708 }
1709 if ((mp = *mpp) == NULL)
1710 return (0);
1711
1712 /*
1713 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1714 * a vfs_ref().
1715 * As long as a vnode is not provided we need to acquire a
1716 * refcount for the provided mountpoint too, in order to
1717 * emulate a vfs_ref().
1718 */
1719 MNT_ILOCK(mp);
1720 if (vp == NULL && (flags & V_MNTREF) == 0)
1721 MNT_REF(mp);
1722
1723 return (vn_start_write_locked(mp, flags));
1724 }
1725
1726 /*
1727 * Secondary suspension. Used by operations such as vop_inactive
1728 * routines that are needed by the higher level functions. These
1729 * are allowed to proceed until all the higher level functions have
1730 * completed (indicated by mnt_writeopcount dropping to zero). At that
1731 * time, these operations are halted until the suspension is over.
1732 */
1733 int
1734 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags)
1735 {
1736 struct mount *mp;
1737 int error;
1738
1739 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1740 ("V_MNTREF requires mp"));
1741
1742 retry:
1743 if (vp != NULL) {
1744 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1745 *mpp = NULL;
1746 if (error != EOPNOTSUPP)
1747 return (error);
1748 return (0);
1749 }
1750 }
1751 /*
1752 * If we are not suspended or have not yet reached suspended
1753 * mode, then let the operation proceed.
1754 */
1755 if ((mp = *mpp) == NULL)
1756 return (0);
1757
1758 /*
1759 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1760 * a vfs_ref().
1761 * As long as a vnode is not provided we need to acquire a
1762 * refcount for the provided mountpoint too, in order to
1763 * emulate a vfs_ref().
1764 */
1765 MNT_ILOCK(mp);
1766 if (vp == NULL && (flags & V_MNTREF) == 0)
1767 MNT_REF(mp);
1768 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
1769 mp->mnt_secondary_writes++;
1770 mp->mnt_secondary_accwrites++;
1771 MNT_IUNLOCK(mp);
1772 return (0);
1773 }
1774 if (flags & V_NOWAIT) {
1775 MNT_REL(mp);
1776 MNT_IUNLOCK(mp);
1777 return (EWOULDBLOCK);
1778 }
1779 /*
1780 * Wait for the suspension to finish.
1781 */
1782 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP |
1783 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0),
1784 "suspfs", 0);
1785 vfs_rel(mp);
1786 if (error == 0)
1787 goto retry;
1788 return (error);
1789 }
1790
1791 /*
1792 * Filesystem write operation has completed. If we are suspending and this
1793 * operation is the last one, notify the suspender that the suspension is
1794 * now in effect.
1795 */
1796 void
1797 vn_finished_write(mp)
1798 struct mount *mp;
1799 {
1800 if (mp == NULL)
1801 return;
1802 MNT_ILOCK(mp);
1803 MNT_REL(mp);
1804 mp->mnt_writeopcount--;
1805 if (mp->mnt_writeopcount < 0)
1806 panic("vn_finished_write: neg cnt");
1807 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1808 mp->mnt_writeopcount <= 0)
1809 wakeup(&mp->mnt_writeopcount);
1810 MNT_IUNLOCK(mp);
1811 }
1812
1813
1814 /*
1815 * Filesystem secondary write operation has completed. If we are
1816 * suspending and this operation is the last one, notify the suspender
1817 * that the suspension is now in effect.
1818 */
1819 void
1820 vn_finished_secondary_write(mp)
1821 struct mount *mp;
1822 {
1823 if (mp == NULL)
1824 return;
1825 MNT_ILOCK(mp);
1826 MNT_REL(mp);
1827 mp->mnt_secondary_writes--;
1828 if (mp->mnt_secondary_writes < 0)
1829 panic("vn_finished_secondary_write: neg cnt");
1830 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1831 mp->mnt_secondary_writes <= 0)
1832 wakeup(&mp->mnt_secondary_writes);
1833 MNT_IUNLOCK(mp);
1834 }
1835
1836
1837
1838 /*
1839 * Request a filesystem to suspend write operations.
1840 */
1841 int
1842 vfs_write_suspend(struct mount *mp, int flags)
1843 {
1844 int error;
1845
1846 MNT_ILOCK(mp);
1847 if (mp->mnt_susp_owner == curthread) {
1848 MNT_IUNLOCK(mp);
1849 return (EALREADY);
1850 }
1851 while (mp->mnt_kern_flag & MNTK_SUSPEND)
1852 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0);
1853
1854 /*
1855 * Unmount holds a write reference on the mount point. If we
1856 * own busy reference and drain for writers, we deadlock with
1857 * the reference draining in the unmount path. Callers of
1858 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if
1859 * vfs_busy() reference is owned and caller is not in the
1860 * unmount context.
1861 */
1862 if ((flags & VS_SKIP_UNMOUNT) != 0 &&
1863 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
1864 MNT_IUNLOCK(mp);
1865 return (EBUSY);
1866 }
1867
1868 mp->mnt_kern_flag |= MNTK_SUSPEND;
1869 mp->mnt_susp_owner = curthread;
1870 if (mp->mnt_writeopcount > 0)
1871 (void) msleep(&mp->mnt_writeopcount,
1872 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0);
1873 else
1874 MNT_IUNLOCK(mp);
1875 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0)
1876 vfs_write_resume(mp, 0);
1877 return (error);
1878 }
1879
1880 /*
1881 * Request a filesystem to resume write operations.
1882 */
1883 void
1884 vfs_write_resume(struct mount *mp, int flags)
1885 {
1886
1887 MNT_ILOCK(mp);
1888 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1889 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
1890 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 |
1891 MNTK_SUSPENDED);
1892 mp->mnt_susp_owner = NULL;
1893 wakeup(&mp->mnt_writeopcount);
1894 wakeup(&mp->mnt_flag);
1895 curthread->td_pflags &= ~TDP_IGNSUSP;
1896 if ((flags & VR_START_WRITE) != 0) {
1897 MNT_REF(mp);
1898 mp->mnt_writeopcount++;
1899 }
1900 MNT_IUNLOCK(mp);
1901 if ((flags & VR_NO_SUSPCLR) == 0)
1902 VFS_SUSP_CLEAN(mp);
1903 } else if ((flags & VR_START_WRITE) != 0) {
1904 MNT_REF(mp);
1905 vn_start_write_locked(mp, 0);
1906 } else {
1907 MNT_IUNLOCK(mp);
1908 }
1909 }
1910
1911 /*
1912 * Helper loop around vfs_write_suspend() for filesystem unmount VFS
1913 * methods.
1914 */
1915 int
1916 vfs_write_suspend_umnt(struct mount *mp)
1917 {
1918 int error;
1919
1920 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
1921 ("vfs_write_suspend_umnt: recursed"));
1922
1923 /* dounmount() already called vn_start_write(). */
1924 for (;;) {
1925 vn_finished_write(mp);
1926 error = vfs_write_suspend(mp, 0);
1927 if (error != 0) {
1928 vn_start_write(NULL, &mp, V_WAIT);
1929 return (error);
1930 }
1931 MNT_ILOCK(mp);
1932 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0)
1933 break;
1934 MNT_IUNLOCK(mp);
1935 vn_start_write(NULL, &mp, V_WAIT);
1936 }
1937 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2);
1938 wakeup(&mp->mnt_flag);
1939 MNT_IUNLOCK(mp);
1940 curthread->td_pflags |= TDP_IGNSUSP;
1941 return (0);
1942 }
1943
1944 /*
1945 * Implement kqueues for files by translating it to vnode operation.
1946 */
1947 static int
1948 vn_kqfilter(struct file *fp, struct knote *kn)
1949 {
1950
1951 return (VOP_KQFILTER(fp->f_vnode, kn));
1952 }
1953
1954 /*
1955 * Simplified in-kernel wrapper calls for extended attribute access.
1956 * Both calls pass in a NULL credential, authorizing as "kernel" access.
1957 * Set IO_NODELOCKED in ioflg if the vnode is already locked.
1958 */
1959 int
1960 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace,
1961 const char *attrname, int *buflen, char *buf, struct thread *td)
1962 {
1963 struct uio auio;
1964 struct iovec iov;
1965 int error;
1966
1967 iov.iov_len = *buflen;
1968 iov.iov_base = buf;
1969
1970 auio.uio_iov = &iov;
1971 auio.uio_iovcnt = 1;
1972 auio.uio_rw = UIO_READ;
1973 auio.uio_segflg = UIO_SYSSPACE;
1974 auio.uio_td = td;
1975 auio.uio_offset = 0;
1976 auio.uio_resid = *buflen;
1977
1978 if ((ioflg & IO_NODELOCKED) == 0)
1979 vn_lock(vp, LK_SHARED | LK_RETRY);
1980
1981 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
1982
1983 /* authorize attribute retrieval as kernel */
1984 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL,
1985 td);
1986
1987 if ((ioflg & IO_NODELOCKED) == 0)
1988 VOP_UNLOCK(vp, 0);
1989
1990 if (error == 0) {
1991 *buflen = *buflen - auio.uio_resid;
1992 }
1993
1994 return (error);
1995 }
1996
1997 /*
1998 * XXX failure mode if partially written?
1999 */
2000 int
2001 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace,
2002 const char *attrname, int buflen, char *buf, struct thread *td)
2003 {
2004 struct uio auio;
2005 struct iovec iov;
2006 struct mount *mp;
2007 int error;
2008
2009 iov.iov_len = buflen;
2010 iov.iov_base = buf;
2011
2012 auio.uio_iov = &iov;
2013 auio.uio_iovcnt = 1;
2014 auio.uio_rw = UIO_WRITE;
2015 auio.uio_segflg = UIO_SYSSPACE;
2016 auio.uio_td = td;
2017 auio.uio_offset = 0;
2018 auio.uio_resid = buflen;
2019
2020 if ((ioflg & IO_NODELOCKED) == 0) {
2021 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2022 return (error);
2023 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2024 }
2025
2026 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2027
2028 /* authorize attribute setting as kernel */
2029 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, 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 int
2040 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
2041 const char *attrname, struct thread *td)
2042 {
2043 struct mount *mp;
2044 int error;
2045
2046 if ((ioflg & IO_NODELOCKED) == 0) {
2047 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2048 return (error);
2049 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2050 }
2051
2052 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2053
2054 /* authorize attribute removal as kernel */
2055 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td);
2056 if (error == EOPNOTSUPP)
2057 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL,
2058 NULL, td);
2059
2060 if ((ioflg & IO_NODELOCKED) == 0) {
2061 vn_finished_write(mp);
2062 VOP_UNLOCK(vp, 0);
2063 }
2064
2065 return (error);
2066 }
2067
2068 static int
2069 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags,
2070 struct vnode **rvp)
2071 {
2072
2073 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp));
2074 }
2075
2076 int
2077 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp)
2078 {
2079
2080 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino,
2081 lkflags, rvp));
2082 }
2083
2084 int
2085 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg,
2086 int lkflags, struct vnode **rvp)
2087 {
2088 struct mount *mp;
2089 int ltype, error;
2090
2091 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get");
2092 mp = vp->v_mount;
2093 ltype = VOP_ISLOCKED(vp);
2094 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED,
2095 ("vn_vget_ino: vp not locked"));
2096 error = vfs_busy(mp, MBF_NOWAIT);
2097 if (error != 0) {
2098 vfs_ref(mp);
2099 VOP_UNLOCK(vp, 0);
2100 error = vfs_busy(mp, 0);
2101 vn_lock(vp, ltype | LK_RETRY);
2102 vfs_rel(mp);
2103 if (error != 0)
2104 return (ENOENT);
2105 if (vp->v_iflag & VI_DOOMED) {
2106 vfs_unbusy(mp);
2107 return (ENOENT);
2108 }
2109 }
2110 VOP_UNLOCK(vp, 0);
2111 error = alloc(mp, alloc_arg, lkflags, rvp);
2112 vfs_unbusy(mp);
2113 if (*rvp != vp)
2114 vn_lock(vp, ltype | LK_RETRY);
2115 if (vp->v_iflag & VI_DOOMED) {
2116 if (error == 0) {
2117 if (*rvp == vp)
2118 vunref(vp);
2119 else
2120 vput(*rvp);
2121 }
2122 error = ENOENT;
2123 }
2124 return (error);
2125 }
2126
2127 int
2128 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
2129 const struct thread *td)
2130 {
2131
2132 if (vp->v_type != VREG || td == NULL)
2133 return (0);
2134 PROC_LOCK(td->td_proc);
2135 if ((uoff_t)uio->uio_offset + uio->uio_resid >
2136 lim_cur(td->td_proc, RLIMIT_FSIZE)) {
2137 kern_psignal(td->td_proc, SIGXFSZ);
2138 PROC_UNLOCK(td->td_proc);
2139 return (EFBIG);
2140 }
2141 PROC_UNLOCK(td->td_proc);
2142 return (0);
2143 }
2144
2145 int
2146 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
2147 struct thread *td)
2148 {
2149 struct vnode *vp;
2150
2151 vp = fp->f_vnode;
2152 #ifdef AUDIT
2153 vn_lock(vp, LK_SHARED | LK_RETRY);
2154 AUDIT_ARG_VNODE1(vp);
2155 VOP_UNLOCK(vp, 0);
2156 #endif
2157 return (setfmode(td, active_cred, vp, mode));
2158 }
2159
2160 int
2161 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
2162 struct thread *td)
2163 {
2164 struct vnode *vp;
2165
2166 vp = fp->f_vnode;
2167 #ifdef AUDIT
2168 vn_lock(vp, LK_SHARED | LK_RETRY);
2169 AUDIT_ARG_VNODE1(vp);
2170 VOP_UNLOCK(vp, 0);
2171 #endif
2172 return (setfown(td, active_cred, vp, uid, gid));
2173 }
2174
2175 void
2176 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
2177 {
2178 vm_object_t object;
2179
2180 if ((object = vp->v_object) == NULL)
2181 return;
2182 VM_OBJECT_WLOCK(object);
2183 vm_object_page_remove(object, start, end, 0);
2184 VM_OBJECT_WUNLOCK(object);
2185 }
2186
2187 int
2188 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
2189 {
2190 struct vattr va;
2191 daddr_t bn, bnp;
2192 uint64_t bsize;
2193 off_t noff;
2194 int error;
2195
2196 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
2197 ("Wrong command %lu", cmd));
2198
2199 if (vn_lock(vp, LK_SHARED) != 0)
2200 return (EBADF);
2201 if (vp->v_type != VREG) {
2202 error = ENOTTY;
2203 goto unlock;
2204 }
2205 error = VOP_GETATTR(vp, &va, cred);
2206 if (error != 0)
2207 goto unlock;
2208 noff = *off;
2209 if (noff >= va.va_size) {
2210 error = ENXIO;
2211 goto unlock;
2212 }
2213 bsize = vp->v_mount->mnt_stat.f_iosize;
2214 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize) {
2215 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL);
2216 if (error == EOPNOTSUPP) {
2217 error = ENOTTY;
2218 goto unlock;
2219 }
2220 if ((bnp == -1 && cmd == FIOSEEKHOLE) ||
2221 (bnp != -1 && cmd == FIOSEEKDATA)) {
2222 noff = bn * bsize;
2223 if (noff < *off)
2224 noff = *off;
2225 goto unlock;
2226 }
2227 }
2228 if (noff > va.va_size)
2229 noff = va.va_size;
2230 /* noff == va.va_size. There is an implicit hole at the end of file. */
2231 if (cmd == FIOSEEKDATA)
2232 error = ENXIO;
2233 unlock:
2234 VOP_UNLOCK(vp, 0);
2235 if (error == 0)
2236 *off = noff;
2237 return (error);
2238 }
2239
2240 int
2241 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
2242 {
2243 struct ucred *cred;
2244 struct vnode *vp;
2245 struct vattr vattr;
2246 off_t foffset, size;
2247 int error, noneg;
2248
2249 cred = td->td_ucred;
2250 vp = fp->f_vnode;
2251 foffset = foffset_lock(fp, 0);
2252 noneg = (vp->v_type != VCHR);
2253 error = 0;
2254 switch (whence) {
2255 case L_INCR:
2256 if (noneg &&
2257 (foffset < 0 ||
2258 (offset > 0 && foffset > OFF_MAX - offset))) {
2259 error = EOVERFLOW;
2260 break;
2261 }
2262 offset += foffset;
2263 break;
2264 case L_XTND:
2265 vn_lock(vp, LK_SHARED | LK_RETRY);
2266 error = VOP_GETATTR(vp, &vattr, cred);
2267 VOP_UNLOCK(vp, 0);
2268 if (error)
2269 break;
2270
2271 /*
2272 * If the file references a disk device, then fetch
2273 * the media size and use that to determine the ending
2274 * offset.
2275 */
2276 if (vattr.va_size == 0 && vp->v_type == VCHR &&
2277 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0)
2278 vattr.va_size = size;
2279 if (noneg &&
2280 (vattr.va_size > OFF_MAX ||
2281 (offset > 0 && vattr.va_size > OFF_MAX - offset))) {
2282 error = EOVERFLOW;
2283 break;
2284 }
2285 offset += vattr.va_size;
2286 break;
2287 case L_SET:
2288 break;
2289 case SEEK_DATA:
2290 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td);
2291 break;
2292 case SEEK_HOLE:
2293 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td);
2294 break;
2295 default:
2296 error = EINVAL;
2297 }
2298 if (error == 0 && noneg && offset < 0)
2299 error = EINVAL;
2300 if (error != 0)
2301 goto drop;
2302 VFS_KNOTE_UNLOCKED(vp, 0);
2303 *(off_t *)(td->td_retval) = offset;
2304 drop:
2305 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
2306 return (error);
2307 }
2308
2309 int
2310 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred,
2311 struct thread *td)
2312 {
2313 int error;
2314
2315 /*
2316 * Grant permission if the caller is the owner of the file, or
2317 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on
2318 * on the file. If the time pointer is null, then write
2319 * permission on the file is also sufficient.
2320 *
2321 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes:
2322 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES
2323 * will be allowed to set the times [..] to the current
2324 * server time.
2325 */
2326 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td);
2327 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0)
2328 error = VOP_ACCESS(vp, VWRITE, cred, td);
2329 return (error);
2330 }
Cache object: 1e89e2c7ff1bf47db73160d15520e003
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