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/10.4/sys/kern/vfs_vnops.c 338606 2018-09-12 05:07:35Z gordon $");
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 static int
416 vn_close1(struct vnode *vp, int flags, struct ucred *file_cred,
417 struct thread *td, bool keep_ref)
418 {
419 struct mount *mp;
420 int error, lock_flags;
421
422 if (vp->v_type != VFIFO && (flags & FWRITE) == 0 &&
423 MNT_EXTENDED_SHARED(vp->v_mount))
424 lock_flags = LK_SHARED;
425 else
426 lock_flags = LK_EXCLUSIVE;
427
428 vn_start_write(vp, &mp, V_WAIT);
429 vn_lock(vp, lock_flags | LK_RETRY);
430 if (flags & FWRITE) {
431 VNASSERT(vp->v_writecount > 0, vp,
432 ("vn_close: negative writecount"));
433 VOP_ADD_WRITECOUNT(vp, -1);
434 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
435 __func__, vp, vp->v_writecount);
436 }
437 error = VOP_CLOSE(vp, flags, file_cred, td);
438 if (keep_ref)
439 VOP_UNLOCK(vp, 0);
440 else
441 vput(vp);
442 vn_finished_write(mp);
443 return (error);
444 }
445
446 int
447 vn_close(struct vnode *vp, int flags, struct ucred *file_cred,
448 struct thread *td)
449 {
450
451 return (vn_close1(vp, flags, file_cred, td, false));
452 }
453
454 /*
455 * Heuristic to detect sequential operation.
456 */
457 static int
458 sequential_heuristic(struct uio *uio, struct file *fp)
459 {
460
461 ASSERT_VOP_LOCKED(fp->f_vnode, __func__);
462 if (fp->f_flag & FRDAHEAD)
463 return (fp->f_seqcount << IO_SEQSHIFT);
464
465 /*
466 * Offset 0 is handled specially. open() sets f_seqcount to 1 so
467 * that the first I/O is normally considered to be slightly
468 * sequential. Seeking to offset 0 doesn't change sequentiality
469 * unless previous seeks have reduced f_seqcount to 0, in which
470 * case offset 0 is not special.
471 */
472 if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
473 uio->uio_offset == fp->f_nextoff) {
474 /*
475 * f_seqcount is in units of fixed-size blocks so that it
476 * depends mainly on the amount of sequential I/O and not
477 * much on the number of sequential I/O's. The fixed size
478 * of 16384 is hard-coded here since it is (not quite) just
479 * a magic size that works well here. This size is more
480 * closely related to the best I/O size for real disks than
481 * to any block size used by software.
482 */
483 fp->f_seqcount += howmany(uio->uio_resid, 16384);
484 if (fp->f_seqcount > IO_SEQMAX)
485 fp->f_seqcount = IO_SEQMAX;
486 return (fp->f_seqcount << IO_SEQSHIFT);
487 }
488
489 /* Not sequential. Quickly draw-down sequentiality. */
490 if (fp->f_seqcount > 1)
491 fp->f_seqcount = 1;
492 else
493 fp->f_seqcount = 0;
494 return (0);
495 }
496
497 /*
498 * Package up an I/O request on a vnode into a uio and do it.
499 */
500 int
501 vn_rdwr(enum uio_rw rw, struct vnode *vp, void *base, int len, off_t offset,
502 enum uio_seg segflg, int ioflg, struct ucred *active_cred,
503 struct ucred *file_cred, ssize_t *aresid, struct thread *td)
504 {
505 struct uio auio;
506 struct iovec aiov;
507 struct mount *mp;
508 struct ucred *cred;
509 void *rl_cookie;
510 struct vn_io_fault_args args;
511 int error, lock_flags;
512
513 if (offset < 0 && vp->v_type != VCHR)
514 return (EINVAL);
515 auio.uio_iov = &aiov;
516 auio.uio_iovcnt = 1;
517 aiov.iov_base = base;
518 aiov.iov_len = len;
519 auio.uio_resid = len;
520 auio.uio_offset = offset;
521 auio.uio_segflg = segflg;
522 auio.uio_rw = rw;
523 auio.uio_td = td;
524 error = 0;
525
526 if ((ioflg & IO_NODELOCKED) == 0) {
527 if ((ioflg & IO_RANGELOCKED) == 0) {
528 if (rw == UIO_READ) {
529 rl_cookie = vn_rangelock_rlock(vp, offset,
530 offset + len);
531 } else {
532 rl_cookie = vn_rangelock_wlock(vp, offset,
533 offset + len);
534 }
535 } else
536 rl_cookie = NULL;
537 mp = NULL;
538 if (rw == UIO_WRITE) {
539 if (vp->v_type != VCHR &&
540 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH))
541 != 0)
542 goto out;
543 if (MNT_SHARED_WRITES(mp) ||
544 ((mp == NULL) && MNT_SHARED_WRITES(vp->v_mount)))
545 lock_flags = LK_SHARED;
546 else
547 lock_flags = LK_EXCLUSIVE;
548 } else
549 lock_flags = LK_SHARED;
550 vn_lock(vp, lock_flags | LK_RETRY);
551 } else
552 rl_cookie = NULL;
553
554 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
555 #ifdef MAC
556 if ((ioflg & IO_NOMACCHECK) == 0) {
557 if (rw == UIO_READ)
558 error = mac_vnode_check_read(active_cred, file_cred,
559 vp);
560 else
561 error = mac_vnode_check_write(active_cred, file_cred,
562 vp);
563 }
564 #endif
565 if (error == 0) {
566 if (file_cred != NULL)
567 cred = file_cred;
568 else
569 cred = active_cred;
570 if (do_vn_io_fault(vp, &auio)) {
571 args.kind = VN_IO_FAULT_VOP;
572 args.cred = cred;
573 args.flags = ioflg;
574 args.args.vop_args.vp = vp;
575 error = vn_io_fault1(vp, &auio, &args, td);
576 } else if (rw == UIO_READ) {
577 error = VOP_READ(vp, &auio, ioflg, cred);
578 } else /* if (rw == UIO_WRITE) */ {
579 error = VOP_WRITE(vp, &auio, ioflg, cred);
580 }
581 }
582 if (aresid)
583 *aresid = auio.uio_resid;
584 else
585 if (auio.uio_resid && error == 0)
586 error = EIO;
587 if ((ioflg & IO_NODELOCKED) == 0) {
588 VOP_UNLOCK(vp, 0);
589 if (mp != NULL)
590 vn_finished_write(mp);
591 }
592 out:
593 if (rl_cookie != NULL)
594 vn_rangelock_unlock(vp, rl_cookie);
595 return (error);
596 }
597
598 /*
599 * Package up an I/O request on a vnode into a uio and do it. The I/O
600 * request is split up into smaller chunks and we try to avoid saturating
601 * the buffer cache while potentially holding a vnode locked, so we
602 * check bwillwrite() before calling vn_rdwr(). We also call kern_yield()
603 * to give other processes a chance to lock the vnode (either other processes
604 * core'ing the same binary, or unrelated processes scanning the directory).
605 */
606 int
607 vn_rdwr_inchunks(rw, vp, base, len, offset, segflg, ioflg, active_cred,
608 file_cred, aresid, td)
609 enum uio_rw rw;
610 struct vnode *vp;
611 void *base;
612 size_t len;
613 off_t offset;
614 enum uio_seg segflg;
615 int ioflg;
616 struct ucred *active_cred;
617 struct ucred *file_cred;
618 size_t *aresid;
619 struct thread *td;
620 {
621 int error = 0;
622 ssize_t iaresid;
623
624 do {
625 int chunk;
626
627 /*
628 * Force `offset' to a multiple of MAXBSIZE except possibly
629 * for the first chunk, so that filesystems only need to
630 * write full blocks except possibly for the first and last
631 * chunks.
632 */
633 chunk = MAXBSIZE - (uoff_t)offset % MAXBSIZE;
634
635 if (chunk > len)
636 chunk = len;
637 if (rw != UIO_READ && vp->v_type == VREG)
638 bwillwrite();
639 iaresid = 0;
640 error = vn_rdwr(rw, vp, base, chunk, offset, segflg,
641 ioflg, active_cred, file_cred, &iaresid, td);
642 len -= chunk; /* aresid calc already includes length */
643 if (error)
644 break;
645 offset += chunk;
646 base = (char *)base + chunk;
647 kern_yield(PRI_USER);
648 } while (len);
649 if (aresid)
650 *aresid = len + iaresid;
651 return (error);
652 }
653
654 off_t
655 foffset_lock(struct file *fp, int flags)
656 {
657 struct mtx *mtxp;
658 off_t res;
659
660 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
661
662 #if OFF_MAX <= LONG_MAX
663 /*
664 * Caller only wants the current f_offset value. Assume that
665 * the long and shorter integer types reads are atomic.
666 */
667 if ((flags & FOF_NOLOCK) != 0)
668 return (fp->f_offset);
669 #endif
670
671 /*
672 * According to McKusick the vn lock was protecting f_offset here.
673 * It is now protected by the FOFFSET_LOCKED flag.
674 */
675 mtxp = mtx_pool_find(mtxpool_sleep, fp);
676 mtx_lock(mtxp);
677 if ((flags & FOF_NOLOCK) == 0) {
678 while (fp->f_vnread_flags & FOFFSET_LOCKED) {
679 fp->f_vnread_flags |= FOFFSET_LOCK_WAITING;
680 msleep(&fp->f_vnread_flags, mtxp, PUSER -1,
681 "vofflock", 0);
682 }
683 fp->f_vnread_flags |= FOFFSET_LOCKED;
684 }
685 res = fp->f_offset;
686 mtx_unlock(mtxp);
687 return (res);
688 }
689
690 void
691 foffset_unlock(struct file *fp, off_t val, int flags)
692 {
693 struct mtx *mtxp;
694
695 KASSERT((flags & FOF_OFFSET) == 0, ("FOF_OFFSET passed"));
696
697 #if OFF_MAX <= LONG_MAX
698 if ((flags & FOF_NOLOCK) != 0) {
699 if ((flags & FOF_NOUPDATE) == 0)
700 fp->f_offset = val;
701 if ((flags & FOF_NEXTOFF) != 0)
702 fp->f_nextoff = val;
703 return;
704 }
705 #endif
706
707 mtxp = mtx_pool_find(mtxpool_sleep, fp);
708 mtx_lock(mtxp);
709 if ((flags & FOF_NOUPDATE) == 0)
710 fp->f_offset = val;
711 if ((flags & FOF_NEXTOFF) != 0)
712 fp->f_nextoff = val;
713 if ((flags & FOF_NOLOCK) == 0) {
714 KASSERT((fp->f_vnread_flags & FOFFSET_LOCKED) != 0,
715 ("Lost FOFFSET_LOCKED"));
716 if (fp->f_vnread_flags & FOFFSET_LOCK_WAITING)
717 wakeup(&fp->f_vnread_flags);
718 fp->f_vnread_flags = 0;
719 }
720 mtx_unlock(mtxp);
721 }
722
723 void
724 foffset_lock_uio(struct file *fp, struct uio *uio, int flags)
725 {
726
727 if ((flags & FOF_OFFSET) == 0)
728 uio->uio_offset = foffset_lock(fp, flags);
729 }
730
731 void
732 foffset_unlock_uio(struct file *fp, struct uio *uio, int flags)
733 {
734
735 if ((flags & FOF_OFFSET) == 0)
736 foffset_unlock(fp, uio->uio_offset, flags);
737 }
738
739 static int
740 get_advice(struct file *fp, struct uio *uio)
741 {
742 struct mtx *mtxp;
743 int ret;
744
745 ret = POSIX_FADV_NORMAL;
746 if (fp->f_advice == NULL || fp->f_vnode->v_type != VREG)
747 return (ret);
748
749 mtxp = mtx_pool_find(mtxpool_sleep, fp);
750 mtx_lock(mtxp);
751 if (fp->f_advice != NULL &&
752 uio->uio_offset >= fp->f_advice->fa_start &&
753 uio->uio_offset + uio->uio_resid <= fp->f_advice->fa_end)
754 ret = fp->f_advice->fa_advice;
755 mtx_unlock(mtxp);
756 return (ret);
757 }
758
759 /*
760 * File table vnode read routine.
761 */
762 static int
763 vn_read(fp, uio, active_cred, flags, td)
764 struct file *fp;
765 struct uio *uio;
766 struct ucred *active_cred;
767 int flags;
768 struct thread *td;
769 {
770 struct vnode *vp;
771 struct mtx *mtxp;
772 int error, ioflag;
773 int advice;
774 off_t offset, start, end;
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 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 offset != uio->uio_offset) {
809 /*
810 * Use POSIX_FADV_DONTNEED to flush clean pages and
811 * buffers for the backing file after a
812 * POSIX_FADV_NOREUSE read(2). To optimize the common
813 * case of using POSIX_FADV_NOREUSE with sequential
814 * access, track the previous implicit DONTNEED
815 * request and grow this request to include the
816 * current read(2) in addition to the previous
817 * DONTNEED. With purely sequential access this will
818 * cause the DONTNEED requests to continously grow to
819 * cover all of the previously read regions of the
820 * file. This allows filesystem blocks that are
821 * accessed by multiple calls to read(2) to be flushed
822 * once the last read(2) finishes.
823 */
824 start = offset;
825 end = uio->uio_offset - 1;
826 mtxp = mtx_pool_find(mtxpool_sleep, fp);
827 mtx_lock(mtxp);
828 if (fp->f_advice != NULL &&
829 fp->f_advice->fa_advice == POSIX_FADV_NOREUSE) {
830 if (start != 0 && fp->f_advice->fa_prevend + 1 == start)
831 start = fp->f_advice->fa_prevstart;
832 else if (fp->f_advice->fa_prevstart != 0 &&
833 fp->f_advice->fa_prevstart == end + 1)
834 end = fp->f_advice->fa_prevend;
835 fp->f_advice->fa_prevstart = start;
836 fp->f_advice->fa_prevend = end;
837 }
838 mtx_unlock(mtxp);
839 error = VOP_ADVISE(vp, start, end, POSIX_FADV_DONTNEED);
840 }
841 return (error);
842 }
843
844 /*
845 * File table vnode write routine.
846 */
847 static int
848 vn_write(fp, uio, active_cred, flags, td)
849 struct file *fp;
850 struct uio *uio;
851 struct ucred *active_cred;
852 int flags;
853 struct thread *td;
854 {
855 struct vnode *vp;
856 struct mount *mp;
857 struct mtx *mtxp;
858 int error, ioflag, lock_flags;
859 int advice;
860 off_t offset, start, end;
861
862 KASSERT(uio->uio_td == td, ("uio_td %p is not td %p",
863 uio->uio_td, td));
864 KASSERT(flags & FOF_OFFSET, ("No FOF_OFFSET"));
865 vp = fp->f_vnode;
866 if (vp->v_type == VREG)
867 bwillwrite();
868 ioflag = IO_UNIT;
869 if (vp->v_type == VREG && (fp->f_flag & O_APPEND))
870 ioflag |= IO_APPEND;
871 if (fp->f_flag & FNONBLOCK)
872 ioflag |= IO_NDELAY;
873 if (fp->f_flag & O_DIRECT)
874 ioflag |= IO_DIRECT;
875 if ((fp->f_flag & O_FSYNC) ||
876 (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS)))
877 ioflag |= IO_SYNC;
878 mp = NULL;
879 if (vp->v_type != VCHR &&
880 (error = vn_start_write(vp, &mp, V_WAIT | PCATCH)) != 0)
881 goto unlock;
882
883 advice = get_advice(fp, uio);
884
885 if (MNT_SHARED_WRITES(mp) ||
886 (mp == NULL && MNT_SHARED_WRITES(vp->v_mount))) {
887 lock_flags = LK_SHARED;
888 } else {
889 lock_flags = LK_EXCLUSIVE;
890 }
891
892 vn_lock(vp, lock_flags | LK_RETRY);
893 switch (advice) {
894 case POSIX_FADV_NORMAL:
895 case POSIX_FADV_SEQUENTIAL:
896 case POSIX_FADV_NOREUSE:
897 ioflag |= sequential_heuristic(uio, fp);
898 break;
899 case POSIX_FADV_RANDOM:
900 /* XXX: Is this correct? */
901 break;
902 }
903 offset = uio->uio_offset;
904
905 #ifdef MAC
906 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
907 if (error == 0)
908 #endif
909 error = VOP_WRITE(vp, uio, ioflag, fp->f_cred);
910 fp->f_nextoff = uio->uio_offset;
911 VOP_UNLOCK(vp, 0);
912 if (vp->v_type != VCHR)
913 vn_finished_write(mp);
914 if (error == 0 && advice == POSIX_FADV_NOREUSE &&
915 offset != uio->uio_offset) {
916 /*
917 * Use POSIX_FADV_DONTNEED to flush clean pages and
918 * buffers for the backing file after a
919 * POSIX_FADV_NOREUSE write(2). To optimize the
920 * common case of using POSIX_FADV_NOREUSE with
921 * sequential access, track the previous implicit
922 * DONTNEED request and grow this request to include
923 * the current write(2) in addition to the previous
924 * DONTNEED. With purely sequential access this will
925 * cause the DONTNEED requests to continously grow to
926 * cover all of the previously written regions of the
927 * file.
928 *
929 * Note that the blocks just written are almost
930 * certainly still dirty, so this only works when
931 * VOP_ADVISE() calls from subsequent writes push out
932 * the data written by this write(2) once the backing
933 * buffers are clean. However, as compared to forcing
934 * IO_DIRECT, this gives much saner behavior. Write
935 * clustering is still allowed, and clean pages are
936 * merely moved to the cache page queue rather than
937 * outright thrown away. This means a subsequent
938 * read(2) can still avoid hitting the disk if the
939 * pages have not been reclaimed.
940 *
941 * This does make POSIX_FADV_NOREUSE largely useless
942 * with non-sequential access. However, sequential
943 * access is the more common use case and the flag is
944 * merely advisory.
945 */
946 start = offset;
947 end = uio->uio_offset - 1;
948 mtxp = mtx_pool_find(mtxpool_sleep, fp);
949 mtx_lock(mtxp);
950 if (fp->f_advice != NULL &&
951 fp->f_advice->fa_advice == POSIX_FADV_NOREUSE) {
952 if (start != 0 && fp->f_advice->fa_prevend + 1 == start)
953 start = fp->f_advice->fa_prevstart;
954 else if (fp->f_advice->fa_prevstart != 0 &&
955 fp->f_advice->fa_prevstart == end + 1)
956 end = fp->f_advice->fa_prevend;
957 fp->f_advice->fa_prevstart = start;
958 fp->f_advice->fa_prevend = end;
959 }
960 mtx_unlock(mtxp);
961 error = VOP_ADVISE(vp, start, end, POSIX_FADV_DONTNEED);
962 }
963
964 unlock:
965 return (error);
966 }
967
968 /*
969 * The vn_io_fault() is a wrapper around vn_read() and vn_write() to
970 * prevent the following deadlock:
971 *
972 * Assume that the thread A reads from the vnode vp1 into userspace
973 * buffer buf1 backed by the pages of vnode vp2. If a page in buf1 is
974 * currently not resident, then system ends up with the call chain
975 * vn_read() -> VOP_READ(vp1) -> uiomove() -> [Page Fault] ->
976 * vm_fault(buf1) -> vnode_pager_getpages(vp2) -> VOP_GETPAGES(vp2)
977 * which establishes lock order vp1->vn_lock, then vp2->vn_lock.
978 * If, at the same time, thread B reads from vnode vp2 into buffer buf2
979 * backed by the pages of vnode vp1, and some page in buf2 is not
980 * resident, we get a reversed order vp2->vn_lock, then vp1->vn_lock.
981 *
982 * To prevent the lock order reversal and deadlock, vn_io_fault() does
983 * not allow page faults to happen during VOP_READ() or VOP_WRITE().
984 * Instead, it first tries to do the whole range i/o with pagefaults
985 * disabled. If all pages in the i/o buffer are resident and mapped,
986 * VOP will succeed (ignoring the genuine filesystem errors).
987 * Otherwise, we get back EFAULT, and vn_io_fault() falls back to do
988 * i/o in chunks, with all pages in the chunk prefaulted and held
989 * using vm_fault_quick_hold_pages().
990 *
991 * Filesystems using this deadlock avoidance scheme should use the
992 * array of the held pages from uio, saved in the curthread->td_ma,
993 * instead of doing uiomove(). A helper function
994 * vn_io_fault_uiomove() converts uiomove request into
995 * uiomove_fromphys() over td_ma array.
996 *
997 * Since vnode locks do not cover the whole i/o anymore, rangelocks
998 * make the current i/o request atomic with respect to other i/os and
999 * truncations.
1000 */
1001
1002 /*
1003 * Decode vn_io_fault_args and perform the corresponding i/o.
1004 */
1005 static int
1006 vn_io_fault_doio(struct vn_io_fault_args *args, struct uio *uio,
1007 struct thread *td)
1008 {
1009
1010 switch (args->kind) {
1011 case VN_IO_FAULT_FOP:
1012 return ((args->args.fop_args.doio)(args->args.fop_args.fp,
1013 uio, args->cred, args->flags, td));
1014 case VN_IO_FAULT_VOP:
1015 if (uio->uio_rw == UIO_READ) {
1016 return (VOP_READ(args->args.vop_args.vp, uio,
1017 args->flags, args->cred));
1018 } else if (uio->uio_rw == UIO_WRITE) {
1019 return (VOP_WRITE(args->args.vop_args.vp, uio,
1020 args->flags, args->cred));
1021 }
1022 break;
1023 }
1024 panic("vn_io_fault_doio: unknown kind of io %d %d", args->kind,
1025 uio->uio_rw);
1026 }
1027
1028 static int
1029 vn_io_fault_touch(char *base, const struct uio *uio)
1030 {
1031 int r;
1032
1033 r = fubyte(base);
1034 if (r == -1 || (uio->uio_rw == UIO_READ && subyte(base, r) == -1))
1035 return (EFAULT);
1036 return (0);
1037 }
1038
1039 static int
1040 vn_io_fault_prefault_user(const struct uio *uio)
1041 {
1042 char *base;
1043 const struct iovec *iov;
1044 size_t len;
1045 ssize_t resid;
1046 int error, i;
1047
1048 KASSERT(uio->uio_segflg == UIO_USERSPACE,
1049 ("vn_io_fault_prefault userspace"));
1050
1051 error = i = 0;
1052 iov = uio->uio_iov;
1053 resid = uio->uio_resid;
1054 base = iov->iov_base;
1055 len = iov->iov_len;
1056 while (resid > 0) {
1057 error = vn_io_fault_touch(base, uio);
1058 if (error != 0)
1059 break;
1060 if (len < PAGE_SIZE) {
1061 if (len != 0) {
1062 error = vn_io_fault_touch(base + len - 1, uio);
1063 if (error != 0)
1064 break;
1065 resid -= len;
1066 }
1067 if (++i >= uio->uio_iovcnt)
1068 break;
1069 iov = uio->uio_iov + i;
1070 base = iov->iov_base;
1071 len = iov->iov_len;
1072 } else {
1073 len -= PAGE_SIZE;
1074 base += PAGE_SIZE;
1075 resid -= PAGE_SIZE;
1076 }
1077 }
1078 return (error);
1079 }
1080
1081 /*
1082 * Common code for vn_io_fault(), agnostic to the kind of i/o request.
1083 * Uses vn_io_fault_doio() to make the call to an actual i/o function.
1084 * Used from vn_rdwr() and vn_io_fault(), which encode the i/o request
1085 * into args and call vn_io_fault1() to handle faults during the user
1086 * mode buffer accesses.
1087 */
1088 static int
1089 vn_io_fault1(struct vnode *vp, struct uio *uio, struct vn_io_fault_args *args,
1090 struct thread *td)
1091 {
1092 vm_page_t ma[io_hold_cnt + 2];
1093 struct uio *uio_clone, short_uio;
1094 struct iovec short_iovec[1];
1095 vm_page_t *prev_td_ma;
1096 vm_prot_t prot;
1097 vm_offset_t addr, end;
1098 size_t len, resid;
1099 ssize_t adv;
1100 int error, cnt, save, saveheld, prev_td_ma_cnt;
1101
1102 if (vn_io_fault_prefault) {
1103 error = vn_io_fault_prefault_user(uio);
1104 if (error != 0)
1105 return (error); /* Or ignore ? */
1106 }
1107
1108 prot = uio->uio_rw == UIO_READ ? VM_PROT_WRITE : VM_PROT_READ;
1109
1110 /*
1111 * The UFS follows IO_UNIT directive and replays back both
1112 * uio_offset and uio_resid if an error is encountered during the
1113 * operation. But, since the iovec may be already advanced,
1114 * uio is still in an inconsistent state.
1115 *
1116 * Cache a copy of the original uio, which is advanced to the redo
1117 * point using UIO_NOCOPY below.
1118 */
1119 uio_clone = cloneuio(uio);
1120 resid = uio->uio_resid;
1121
1122 short_uio.uio_segflg = UIO_USERSPACE;
1123 short_uio.uio_rw = uio->uio_rw;
1124 short_uio.uio_td = uio->uio_td;
1125
1126 save = vm_fault_disable_pagefaults();
1127 error = vn_io_fault_doio(args, uio, td);
1128 if (error != EFAULT)
1129 goto out;
1130
1131 atomic_add_long(&vn_io_faults_cnt, 1);
1132 uio_clone->uio_segflg = UIO_NOCOPY;
1133 uiomove(NULL, resid - uio->uio_resid, uio_clone);
1134 uio_clone->uio_segflg = uio->uio_segflg;
1135
1136 saveheld = curthread_pflags_set(TDP_UIOHELD);
1137 prev_td_ma = td->td_ma;
1138 prev_td_ma_cnt = td->td_ma_cnt;
1139
1140 while (uio_clone->uio_resid != 0) {
1141 len = uio_clone->uio_iov->iov_len;
1142 if (len == 0) {
1143 KASSERT(uio_clone->uio_iovcnt >= 1,
1144 ("iovcnt underflow"));
1145 uio_clone->uio_iov++;
1146 uio_clone->uio_iovcnt--;
1147 continue;
1148 }
1149 if (len > io_hold_cnt * PAGE_SIZE)
1150 len = io_hold_cnt * PAGE_SIZE;
1151 addr = (uintptr_t)uio_clone->uio_iov->iov_base;
1152 end = round_page(addr + len);
1153 if (end < addr) {
1154 error = EFAULT;
1155 break;
1156 }
1157 cnt = atop(end - trunc_page(addr));
1158 /*
1159 * A perfectly misaligned address and length could cause
1160 * both the start and the end of the chunk to use partial
1161 * page. +2 accounts for such a situation.
1162 */
1163 cnt = vm_fault_quick_hold_pages(&td->td_proc->p_vmspace->vm_map,
1164 addr, len, prot, ma, io_hold_cnt + 2);
1165 if (cnt == -1) {
1166 error = EFAULT;
1167 break;
1168 }
1169 short_uio.uio_iov = &short_iovec[0];
1170 short_iovec[0].iov_base = (void *)addr;
1171 short_uio.uio_iovcnt = 1;
1172 short_uio.uio_resid = short_iovec[0].iov_len = len;
1173 short_uio.uio_offset = uio_clone->uio_offset;
1174 td->td_ma = ma;
1175 td->td_ma_cnt = cnt;
1176
1177 error = vn_io_fault_doio(args, &short_uio, td);
1178 vm_page_unhold_pages(ma, cnt);
1179 adv = len - short_uio.uio_resid;
1180
1181 uio_clone->uio_iov->iov_base =
1182 (char *)uio_clone->uio_iov->iov_base + adv;
1183 uio_clone->uio_iov->iov_len -= adv;
1184 uio_clone->uio_resid -= adv;
1185 uio_clone->uio_offset += adv;
1186
1187 uio->uio_resid -= adv;
1188 uio->uio_offset += adv;
1189
1190 if (error != 0 || adv == 0)
1191 break;
1192 }
1193 td->td_ma = prev_td_ma;
1194 td->td_ma_cnt = prev_td_ma_cnt;
1195 curthread_pflags_restore(saveheld);
1196 out:
1197 vm_fault_enable_pagefaults(save);
1198 free(uio_clone, M_IOV);
1199 return (error);
1200 }
1201
1202 static int
1203 vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred,
1204 int flags, struct thread *td)
1205 {
1206 fo_rdwr_t *doio;
1207 struct vnode *vp;
1208 void *rl_cookie;
1209 struct vn_io_fault_args args;
1210 int error;
1211
1212 doio = uio->uio_rw == UIO_READ ? vn_read : vn_write;
1213 vp = fp->f_vnode;
1214 foffset_lock_uio(fp, uio, flags);
1215 if (do_vn_io_fault(vp, uio)) {
1216 args.kind = VN_IO_FAULT_FOP;
1217 args.args.fop_args.fp = fp;
1218 args.args.fop_args.doio = doio;
1219 args.cred = active_cred;
1220 args.flags = flags | FOF_OFFSET;
1221 if (uio->uio_rw == UIO_READ) {
1222 rl_cookie = vn_rangelock_rlock(vp, uio->uio_offset,
1223 uio->uio_offset + uio->uio_resid);
1224 } else if ((fp->f_flag & O_APPEND) != 0 ||
1225 (flags & FOF_OFFSET) == 0) {
1226 /* For appenders, punt and lock the whole range. */
1227 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1228 } else {
1229 rl_cookie = vn_rangelock_wlock(vp, uio->uio_offset,
1230 uio->uio_offset + uio->uio_resid);
1231 }
1232 error = vn_io_fault1(vp, uio, &args, td);
1233 vn_rangelock_unlock(vp, rl_cookie);
1234 } else {
1235 error = doio(fp, uio, active_cred, flags | FOF_OFFSET, td);
1236 }
1237 foffset_unlock_uio(fp, uio, flags);
1238 return (error);
1239 }
1240
1241 /*
1242 * Helper function to perform the requested uiomove operation using
1243 * the held pages for io->uio_iov[0].iov_base buffer instead of
1244 * copyin/copyout. Access to the pages with uiomove_fromphys()
1245 * instead of iov_base prevents page faults that could occur due to
1246 * pmap_collect() invalidating the mapping created by
1247 * vm_fault_quick_hold_pages(), or pageout daemon, page laundry or
1248 * object cleanup revoking the write access from page mappings.
1249 *
1250 * Filesystems specified MNTK_NO_IOPF shall use vn_io_fault_uiomove()
1251 * instead of plain uiomove().
1252 */
1253 int
1254 vn_io_fault_uiomove(char *data, int xfersize, struct uio *uio)
1255 {
1256 struct uio transp_uio;
1257 struct iovec transp_iov[1];
1258 struct thread *td;
1259 size_t adv;
1260 int error, pgadv;
1261
1262 td = curthread;
1263 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1264 uio->uio_segflg != UIO_USERSPACE)
1265 return (uiomove(data, xfersize, uio));
1266
1267 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1268 transp_iov[0].iov_base = data;
1269 transp_uio.uio_iov = &transp_iov[0];
1270 transp_uio.uio_iovcnt = 1;
1271 if (xfersize > uio->uio_resid)
1272 xfersize = uio->uio_resid;
1273 transp_uio.uio_resid = transp_iov[0].iov_len = xfersize;
1274 transp_uio.uio_offset = 0;
1275 transp_uio.uio_segflg = UIO_SYSSPACE;
1276 /*
1277 * Since transp_iov points to data, and td_ma page array
1278 * corresponds to original uio->uio_iov, we need to invert the
1279 * direction of the i/o operation as passed to
1280 * uiomove_fromphys().
1281 */
1282 switch (uio->uio_rw) {
1283 case UIO_WRITE:
1284 transp_uio.uio_rw = UIO_READ;
1285 break;
1286 case UIO_READ:
1287 transp_uio.uio_rw = UIO_WRITE;
1288 break;
1289 }
1290 transp_uio.uio_td = uio->uio_td;
1291 error = uiomove_fromphys(td->td_ma,
1292 ((vm_offset_t)uio->uio_iov->iov_base) & PAGE_MASK,
1293 xfersize, &transp_uio);
1294 adv = xfersize - transp_uio.uio_resid;
1295 pgadv =
1296 (((vm_offset_t)uio->uio_iov->iov_base + adv) >> PAGE_SHIFT) -
1297 (((vm_offset_t)uio->uio_iov->iov_base) >> PAGE_SHIFT);
1298 td->td_ma += pgadv;
1299 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1300 pgadv));
1301 td->td_ma_cnt -= pgadv;
1302 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + adv;
1303 uio->uio_iov->iov_len -= adv;
1304 uio->uio_resid -= adv;
1305 uio->uio_offset += adv;
1306 return (error);
1307 }
1308
1309 int
1310 vn_io_fault_pgmove(vm_page_t ma[], vm_offset_t offset, int xfersize,
1311 struct uio *uio)
1312 {
1313 struct thread *td;
1314 vm_offset_t iov_base;
1315 int cnt, pgadv;
1316
1317 td = curthread;
1318 if ((td->td_pflags & TDP_UIOHELD) == 0 ||
1319 uio->uio_segflg != UIO_USERSPACE)
1320 return (uiomove_fromphys(ma, offset, xfersize, uio));
1321
1322 KASSERT(uio->uio_iovcnt == 1, ("uio_iovcnt %d", uio->uio_iovcnt));
1323 cnt = xfersize > uio->uio_resid ? uio->uio_resid : xfersize;
1324 iov_base = (vm_offset_t)uio->uio_iov->iov_base;
1325 switch (uio->uio_rw) {
1326 case UIO_WRITE:
1327 pmap_copy_pages(td->td_ma, iov_base & PAGE_MASK, ma,
1328 offset, cnt);
1329 break;
1330 case UIO_READ:
1331 pmap_copy_pages(ma, offset, td->td_ma, iov_base & PAGE_MASK,
1332 cnt);
1333 break;
1334 }
1335 pgadv = ((iov_base + cnt) >> PAGE_SHIFT) - (iov_base >> PAGE_SHIFT);
1336 td->td_ma += pgadv;
1337 KASSERT(td->td_ma_cnt >= pgadv, ("consumed pages %d %d", td->td_ma_cnt,
1338 pgadv));
1339 td->td_ma_cnt -= pgadv;
1340 uio->uio_iov->iov_base = (char *)(iov_base + cnt);
1341 uio->uio_iov->iov_len -= cnt;
1342 uio->uio_resid -= cnt;
1343 uio->uio_offset += cnt;
1344 return (0);
1345 }
1346
1347
1348 /*
1349 * File table truncate routine.
1350 */
1351 static int
1352 vn_truncate(struct file *fp, off_t length, struct ucred *active_cred,
1353 struct thread *td)
1354 {
1355 struct vattr vattr;
1356 struct mount *mp;
1357 struct vnode *vp;
1358 void *rl_cookie;
1359 int error;
1360
1361 vp = fp->f_vnode;
1362
1363 /*
1364 * Lock the whole range for truncation. Otherwise split i/o
1365 * might happen partly before and partly after the truncation.
1366 */
1367 rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX);
1368 error = vn_start_write(vp, &mp, V_WAIT | PCATCH);
1369 if (error)
1370 goto out1;
1371 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1372 if (vp->v_type == VDIR) {
1373 error = EISDIR;
1374 goto out;
1375 }
1376 #ifdef MAC
1377 error = mac_vnode_check_write(active_cred, fp->f_cred, vp);
1378 if (error)
1379 goto out;
1380 #endif
1381 error = vn_writechk(vp);
1382 if (error == 0) {
1383 VATTR_NULL(&vattr);
1384 vattr.va_size = length;
1385 if ((fp->f_flag & O_FSYNC) != 0)
1386 vattr.va_vaflags |= VA_SYNC;
1387 error = VOP_SETATTR(vp, &vattr, fp->f_cred);
1388 }
1389 out:
1390 VOP_UNLOCK(vp, 0);
1391 vn_finished_write(mp);
1392 out1:
1393 vn_rangelock_unlock(vp, rl_cookie);
1394 return (error);
1395 }
1396
1397 /*
1398 * File table vnode stat routine.
1399 */
1400 static int
1401 vn_statfile(fp, sb, active_cred, td)
1402 struct file *fp;
1403 struct stat *sb;
1404 struct ucred *active_cred;
1405 struct thread *td;
1406 {
1407 struct vnode *vp = fp->f_vnode;
1408 int error;
1409
1410 vn_lock(vp, LK_SHARED | LK_RETRY);
1411 error = vn_stat(vp, sb, active_cred, fp->f_cred, td);
1412 VOP_UNLOCK(vp, 0);
1413
1414 return (error);
1415 }
1416
1417 /*
1418 * Stat a vnode; implementation for the stat syscall
1419 */
1420 int
1421 vn_stat(vp, sb, active_cred, file_cred, td)
1422 struct vnode *vp;
1423 register struct stat *sb;
1424 struct ucred *active_cred;
1425 struct ucred *file_cred;
1426 struct thread *td;
1427 {
1428 struct vattr vattr;
1429 register struct vattr *vap;
1430 int error;
1431 u_short mode;
1432
1433 #ifdef MAC
1434 error = mac_vnode_check_stat(active_cred, file_cred, vp);
1435 if (error)
1436 return (error);
1437 #endif
1438
1439 vap = &vattr;
1440
1441 /*
1442 * Initialize defaults for new and unusual fields, so that file
1443 * systems which don't support these fields don't need to know
1444 * about them.
1445 */
1446 vap->va_birthtime.tv_sec = -1;
1447 vap->va_birthtime.tv_nsec = 0;
1448 vap->va_fsid = VNOVAL;
1449 vap->va_rdev = NODEV;
1450
1451 error = VOP_GETATTR(vp, vap, active_cred);
1452 if (error)
1453 return (error);
1454
1455 /*
1456 * Zero the spare stat fields
1457 */
1458 bzero(sb, sizeof *sb);
1459
1460 /*
1461 * Copy from vattr table
1462 */
1463 if (vap->va_fsid != VNOVAL)
1464 sb->st_dev = vap->va_fsid;
1465 else
1466 sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
1467 sb->st_ino = vap->va_fileid;
1468 mode = vap->va_mode;
1469 switch (vap->va_type) {
1470 case VREG:
1471 mode |= S_IFREG;
1472 break;
1473 case VDIR:
1474 mode |= S_IFDIR;
1475 break;
1476 case VBLK:
1477 mode |= S_IFBLK;
1478 break;
1479 case VCHR:
1480 mode |= S_IFCHR;
1481 break;
1482 case VLNK:
1483 mode |= S_IFLNK;
1484 break;
1485 case VSOCK:
1486 mode |= S_IFSOCK;
1487 break;
1488 case VFIFO:
1489 mode |= S_IFIFO;
1490 break;
1491 default:
1492 return (EBADF);
1493 };
1494 sb->st_mode = mode;
1495 sb->st_nlink = vap->va_nlink;
1496 sb->st_uid = vap->va_uid;
1497 sb->st_gid = vap->va_gid;
1498 sb->st_rdev = vap->va_rdev;
1499 if (vap->va_size > OFF_MAX)
1500 return (EOVERFLOW);
1501 sb->st_size = vap->va_size;
1502 sb->st_atim = vap->va_atime;
1503 sb->st_mtim = vap->va_mtime;
1504 sb->st_ctim = vap->va_ctime;
1505 sb->st_birthtim = vap->va_birthtime;
1506
1507 /*
1508 * According to www.opengroup.org, the meaning of st_blksize is
1509 * "a filesystem-specific preferred I/O block size for this
1510 * object. In some filesystem types, this may vary from file
1511 * to file"
1512 * Use miminum/default of PAGE_SIZE (e.g. for VCHR).
1513 */
1514
1515 sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize);
1516
1517 sb->st_flags = vap->va_flags;
1518 if (priv_check(td, PRIV_VFS_GENERATION))
1519 sb->st_gen = 0;
1520 else
1521 sb->st_gen = vap->va_gen;
1522
1523 sb->st_blocks = vap->va_bytes / S_BLKSIZE;
1524 return (0);
1525 }
1526
1527 /*
1528 * File table vnode ioctl routine.
1529 */
1530 static int
1531 vn_ioctl(fp, com, data, active_cred, td)
1532 struct file *fp;
1533 u_long com;
1534 void *data;
1535 struct ucred *active_cred;
1536 struct thread *td;
1537 {
1538 struct vattr vattr;
1539 struct vnode *vp;
1540 int error;
1541
1542 vp = fp->f_vnode;
1543 switch (vp->v_type) {
1544 case VDIR:
1545 case VREG:
1546 switch (com) {
1547 case FIONREAD:
1548 vn_lock(vp, LK_SHARED | LK_RETRY);
1549 error = VOP_GETATTR(vp, &vattr, active_cred);
1550 VOP_UNLOCK(vp, 0);
1551 if (error == 0)
1552 *(int *)data = vattr.va_size - fp->f_offset;
1553 return (error);
1554 case FIONBIO:
1555 case FIOASYNC:
1556 return (0);
1557 default:
1558 return (VOP_IOCTL(vp, com, data, fp->f_flag,
1559 active_cred, td));
1560 }
1561 default:
1562 return (ENOTTY);
1563 }
1564 }
1565
1566 /*
1567 * File table vnode poll routine.
1568 */
1569 static int
1570 vn_poll(fp, events, active_cred, td)
1571 struct file *fp;
1572 int events;
1573 struct ucred *active_cred;
1574 struct thread *td;
1575 {
1576 struct vnode *vp;
1577 int error;
1578
1579 vp = fp->f_vnode;
1580 #ifdef MAC
1581 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1582 error = mac_vnode_check_poll(active_cred, fp->f_cred, vp);
1583 VOP_UNLOCK(vp, 0);
1584 if (!error)
1585 #endif
1586
1587 error = VOP_POLL(vp, events, fp->f_cred, td);
1588 return (error);
1589 }
1590
1591 /*
1592 * Acquire the requested lock and then check for validity. LK_RETRY
1593 * permits vn_lock to return doomed vnodes.
1594 */
1595 int
1596 _vn_lock(struct vnode *vp, int flags, char *file, int line)
1597 {
1598 int error;
1599
1600 VNASSERT((flags & LK_TYPE_MASK) != 0, vp,
1601 ("vn_lock called with no locktype."));
1602 do {
1603 #ifdef DEBUG_VFS_LOCKS
1604 KASSERT(vp->v_holdcnt != 0,
1605 ("vn_lock %p: zero hold count", vp));
1606 #endif
1607 error = VOP_LOCK1(vp, flags, file, line);
1608 flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */
1609 KASSERT((flags & LK_RETRY) == 0 || error == 0,
1610 ("LK_RETRY set with incompatible flags (0x%x) or an error occurred (%d)",
1611 flags, error));
1612 /*
1613 * Callers specify LK_RETRY if they wish to get dead vnodes.
1614 * If RETRY is not set, we return ENOENT instead.
1615 */
1616 if (error == 0 && vp->v_iflag & VI_DOOMED &&
1617 (flags & LK_RETRY) == 0) {
1618 VOP_UNLOCK(vp, 0);
1619 error = ENOENT;
1620 break;
1621 }
1622 } while (flags & LK_RETRY && error != 0);
1623 return (error);
1624 }
1625
1626 /*
1627 * File table vnode close routine.
1628 */
1629 static int
1630 vn_closefile(fp, td)
1631 struct file *fp;
1632 struct thread *td;
1633 {
1634 struct vnode *vp;
1635 struct flock lf;
1636 int error;
1637 bool ref;
1638
1639 vp = fp->f_vnode;
1640 fp->f_ops = &badfileops;
1641 ref= (fp->f_flag & FHASLOCK) != 0 && fp->f_type == DTYPE_VNODE;
1642
1643 error = vn_close1(vp, fp->f_flag, fp->f_cred, td, ref);
1644
1645 if (__predict_false(ref)) {
1646 lf.l_whence = SEEK_SET;
1647 lf.l_start = 0;
1648 lf.l_len = 0;
1649 lf.l_type = F_UNLCK;
1650 (void) VOP_ADVLOCK(vp, fp, F_UNLCK, &lf, F_FLOCK);
1651 vrele(vp);
1652 }
1653 return (error);
1654 }
1655
1656 /*
1657 * Preparing to start a filesystem write operation. If the operation is
1658 * permitted, then we bump the count of operations in progress and
1659 * proceed. If a suspend request is in progress, we wait until the
1660 * suspension is over, and then proceed.
1661 */
1662 static int
1663 vn_start_write_locked(struct mount *mp, int flags)
1664 {
1665 int error, mflags;
1666
1667 mtx_assert(MNT_MTX(mp), MA_OWNED);
1668 error = 0;
1669
1670 /*
1671 * Check on status of suspension.
1672 */
1673 if ((curthread->td_pflags & TDP_IGNSUSP) == 0 ||
1674 mp->mnt_susp_owner != curthread) {
1675 mflags = ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ?
1676 (flags & PCATCH) : 0) | (PUSER - 1);
1677 while ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1678 if (flags & V_NOWAIT) {
1679 error = EWOULDBLOCK;
1680 goto unlock;
1681 }
1682 error = msleep(&mp->mnt_flag, MNT_MTX(mp), mflags,
1683 "suspfs", 0);
1684 if (error)
1685 goto unlock;
1686 }
1687 }
1688 if (flags & V_XSLEEP)
1689 goto unlock;
1690 mp->mnt_writeopcount++;
1691 unlock:
1692 if (error != 0 || (flags & V_XSLEEP) != 0)
1693 MNT_REL(mp);
1694 MNT_IUNLOCK(mp);
1695 return (error);
1696 }
1697
1698 int
1699 vn_start_write(struct vnode *vp, struct mount **mpp, int flags)
1700 {
1701 struct mount *mp;
1702 int error;
1703
1704 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1705 ("V_MNTREF requires mp"));
1706
1707 error = 0;
1708 /*
1709 * If a vnode is provided, get and return the mount point that
1710 * to which it will write.
1711 */
1712 if (vp != NULL) {
1713 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1714 *mpp = NULL;
1715 if (error != EOPNOTSUPP)
1716 return (error);
1717 return (0);
1718 }
1719 }
1720 if ((mp = *mpp) == NULL)
1721 return (0);
1722
1723 /*
1724 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1725 * a vfs_ref().
1726 * As long as a vnode is not provided we need to acquire a
1727 * refcount for the provided mountpoint too, in order to
1728 * emulate a vfs_ref().
1729 */
1730 MNT_ILOCK(mp);
1731 if (vp == NULL && (flags & V_MNTREF) == 0)
1732 MNT_REF(mp);
1733
1734 return (vn_start_write_locked(mp, flags));
1735 }
1736
1737 /*
1738 * Secondary suspension. Used by operations such as vop_inactive
1739 * routines that are needed by the higher level functions. These
1740 * are allowed to proceed until all the higher level functions have
1741 * completed (indicated by mnt_writeopcount dropping to zero). At that
1742 * time, these operations are halted until the suspension is over.
1743 */
1744 int
1745 vn_start_secondary_write(struct vnode *vp, struct mount **mpp, int flags)
1746 {
1747 struct mount *mp;
1748 int error;
1749
1750 KASSERT((flags & V_MNTREF) == 0 || (*mpp != NULL && vp == NULL),
1751 ("V_MNTREF requires mp"));
1752
1753 retry:
1754 if (vp != NULL) {
1755 if ((error = VOP_GETWRITEMOUNT(vp, mpp)) != 0) {
1756 *mpp = NULL;
1757 if (error != EOPNOTSUPP)
1758 return (error);
1759 return (0);
1760 }
1761 }
1762 /*
1763 * If we are not suspended or have not yet reached suspended
1764 * mode, then let the operation proceed.
1765 */
1766 if ((mp = *mpp) == NULL)
1767 return (0);
1768
1769 /*
1770 * VOP_GETWRITEMOUNT() returns with the mp refcount held through
1771 * a vfs_ref().
1772 * As long as a vnode is not provided we need to acquire a
1773 * refcount for the provided mountpoint too, in order to
1774 * emulate a vfs_ref().
1775 */
1776 MNT_ILOCK(mp);
1777 if (vp == NULL && (flags & V_MNTREF) == 0)
1778 MNT_REF(mp);
1779 if ((mp->mnt_kern_flag & (MNTK_SUSPENDED | MNTK_SUSPEND2)) == 0) {
1780 mp->mnt_secondary_writes++;
1781 mp->mnt_secondary_accwrites++;
1782 MNT_IUNLOCK(mp);
1783 return (0);
1784 }
1785 if (flags & V_NOWAIT) {
1786 MNT_REL(mp);
1787 MNT_IUNLOCK(mp);
1788 return (EWOULDBLOCK);
1789 }
1790 /*
1791 * Wait for the suspension to finish.
1792 */
1793 error = msleep(&mp->mnt_flag, MNT_MTX(mp), (PUSER - 1) | PDROP |
1794 ((mp->mnt_vfc->vfc_flags & VFCF_SBDRY) != 0 ? (flags & PCATCH) : 0),
1795 "suspfs", 0);
1796 vfs_rel(mp);
1797 if (error == 0)
1798 goto retry;
1799 return (error);
1800 }
1801
1802 /*
1803 * Filesystem write operation has completed. If we are suspending and this
1804 * operation is the last one, notify the suspender that the suspension is
1805 * now in effect.
1806 */
1807 void
1808 vn_finished_write(mp)
1809 struct mount *mp;
1810 {
1811 if (mp == NULL)
1812 return;
1813 MNT_ILOCK(mp);
1814 MNT_REL(mp);
1815 mp->mnt_writeopcount--;
1816 if (mp->mnt_writeopcount < 0)
1817 panic("vn_finished_write: neg cnt");
1818 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1819 mp->mnt_writeopcount <= 0)
1820 wakeup(&mp->mnt_writeopcount);
1821 MNT_IUNLOCK(mp);
1822 }
1823
1824
1825 /*
1826 * Filesystem secondary write operation has completed. If we are
1827 * suspending and this operation is the last one, notify the suspender
1828 * that the suspension is now in effect.
1829 */
1830 void
1831 vn_finished_secondary_write(mp)
1832 struct mount *mp;
1833 {
1834 if (mp == NULL)
1835 return;
1836 MNT_ILOCK(mp);
1837 MNT_REL(mp);
1838 mp->mnt_secondary_writes--;
1839 if (mp->mnt_secondary_writes < 0)
1840 panic("vn_finished_secondary_write: neg cnt");
1841 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0 &&
1842 mp->mnt_secondary_writes <= 0)
1843 wakeup(&mp->mnt_secondary_writes);
1844 MNT_IUNLOCK(mp);
1845 }
1846
1847
1848
1849 /*
1850 * Request a filesystem to suspend write operations.
1851 */
1852 int
1853 vfs_write_suspend(struct mount *mp, int flags)
1854 {
1855 int error;
1856
1857 MNT_ILOCK(mp);
1858 if (mp->mnt_susp_owner == curthread) {
1859 MNT_IUNLOCK(mp);
1860 return (EALREADY);
1861 }
1862 while (mp->mnt_kern_flag & MNTK_SUSPEND)
1863 msleep(&mp->mnt_flag, MNT_MTX(mp), PUSER - 1, "wsuspfs", 0);
1864
1865 /*
1866 * Unmount holds a write reference on the mount point. If we
1867 * own busy reference and drain for writers, we deadlock with
1868 * the reference draining in the unmount path. Callers of
1869 * vfs_write_suspend() must specify VS_SKIP_UNMOUNT if
1870 * vfs_busy() reference is owned and caller is not in the
1871 * unmount context.
1872 */
1873 if ((flags & VS_SKIP_UNMOUNT) != 0 &&
1874 (mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
1875 MNT_IUNLOCK(mp);
1876 return (EBUSY);
1877 }
1878
1879 mp->mnt_kern_flag |= MNTK_SUSPEND;
1880 mp->mnt_susp_owner = curthread;
1881 if (mp->mnt_writeopcount > 0)
1882 (void) msleep(&mp->mnt_writeopcount,
1883 MNT_MTX(mp), (PUSER - 1)|PDROP, "suspwt", 0);
1884 else
1885 MNT_IUNLOCK(mp);
1886 if ((error = VFS_SYNC(mp, MNT_SUSPEND)) != 0)
1887 vfs_write_resume(mp, 0);
1888 return (error);
1889 }
1890
1891 /*
1892 * Request a filesystem to resume write operations.
1893 */
1894 void
1895 vfs_write_resume(struct mount *mp, int flags)
1896 {
1897
1898 MNT_ILOCK(mp);
1899 if ((mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
1900 KASSERT(mp->mnt_susp_owner == curthread, ("mnt_susp_owner"));
1901 mp->mnt_kern_flag &= ~(MNTK_SUSPEND | MNTK_SUSPEND2 |
1902 MNTK_SUSPENDED);
1903 mp->mnt_susp_owner = NULL;
1904 wakeup(&mp->mnt_writeopcount);
1905 wakeup(&mp->mnt_flag);
1906 curthread->td_pflags &= ~TDP_IGNSUSP;
1907 if ((flags & VR_START_WRITE) != 0) {
1908 MNT_REF(mp);
1909 mp->mnt_writeopcount++;
1910 }
1911 MNT_IUNLOCK(mp);
1912 if ((flags & VR_NO_SUSPCLR) == 0)
1913 VFS_SUSP_CLEAN(mp);
1914 } else if ((flags & VR_START_WRITE) != 0) {
1915 MNT_REF(mp);
1916 vn_start_write_locked(mp, 0);
1917 } else {
1918 MNT_IUNLOCK(mp);
1919 }
1920 }
1921
1922 /*
1923 * Helper loop around vfs_write_suspend() for filesystem unmount VFS
1924 * methods.
1925 */
1926 int
1927 vfs_write_suspend_umnt(struct mount *mp)
1928 {
1929 int error;
1930
1931 KASSERT((curthread->td_pflags & TDP_IGNSUSP) == 0,
1932 ("vfs_write_suspend_umnt: recursed"));
1933
1934 /* dounmount() already called vn_start_write(). */
1935 for (;;) {
1936 vn_finished_write(mp);
1937 error = vfs_write_suspend(mp, 0);
1938 if (error != 0) {
1939 vn_start_write(NULL, &mp, V_WAIT);
1940 return (error);
1941 }
1942 MNT_ILOCK(mp);
1943 if ((mp->mnt_kern_flag & MNTK_SUSPENDED) != 0)
1944 break;
1945 MNT_IUNLOCK(mp);
1946 vn_start_write(NULL, &mp, V_WAIT);
1947 }
1948 mp->mnt_kern_flag &= ~(MNTK_SUSPENDED | MNTK_SUSPEND2);
1949 wakeup(&mp->mnt_flag);
1950 MNT_IUNLOCK(mp);
1951 curthread->td_pflags |= TDP_IGNSUSP;
1952 return (0);
1953 }
1954
1955 /*
1956 * Implement kqueues for files by translating it to vnode operation.
1957 */
1958 static int
1959 vn_kqfilter(struct file *fp, struct knote *kn)
1960 {
1961
1962 return (VOP_KQFILTER(fp->f_vnode, kn));
1963 }
1964
1965 /*
1966 * Simplified in-kernel wrapper calls for extended attribute access.
1967 * Both calls pass in a NULL credential, authorizing as "kernel" access.
1968 * Set IO_NODELOCKED in ioflg if the vnode is already locked.
1969 */
1970 int
1971 vn_extattr_get(struct vnode *vp, int ioflg, int attrnamespace,
1972 const char *attrname, int *buflen, char *buf, struct thread *td)
1973 {
1974 struct uio auio;
1975 struct iovec iov;
1976 int error;
1977
1978 iov.iov_len = *buflen;
1979 iov.iov_base = buf;
1980
1981 auio.uio_iov = &iov;
1982 auio.uio_iovcnt = 1;
1983 auio.uio_rw = UIO_READ;
1984 auio.uio_segflg = UIO_SYSSPACE;
1985 auio.uio_td = td;
1986 auio.uio_offset = 0;
1987 auio.uio_resid = *buflen;
1988
1989 if ((ioflg & IO_NODELOCKED) == 0)
1990 vn_lock(vp, LK_SHARED | LK_RETRY);
1991
1992 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
1993
1994 /* authorize attribute retrieval as kernel */
1995 error = VOP_GETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, NULL,
1996 td);
1997
1998 if ((ioflg & IO_NODELOCKED) == 0)
1999 VOP_UNLOCK(vp, 0);
2000
2001 if (error == 0) {
2002 *buflen = *buflen - auio.uio_resid;
2003 }
2004
2005 return (error);
2006 }
2007
2008 /*
2009 * XXX failure mode if partially written?
2010 */
2011 int
2012 vn_extattr_set(struct vnode *vp, int ioflg, int attrnamespace,
2013 const char *attrname, int buflen, char *buf, struct thread *td)
2014 {
2015 struct uio auio;
2016 struct iovec iov;
2017 struct mount *mp;
2018 int error;
2019
2020 iov.iov_len = buflen;
2021 iov.iov_base = buf;
2022
2023 auio.uio_iov = &iov;
2024 auio.uio_iovcnt = 1;
2025 auio.uio_rw = UIO_WRITE;
2026 auio.uio_segflg = UIO_SYSSPACE;
2027 auio.uio_td = td;
2028 auio.uio_offset = 0;
2029 auio.uio_resid = buflen;
2030
2031 if ((ioflg & IO_NODELOCKED) == 0) {
2032 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2033 return (error);
2034 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2035 }
2036
2037 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2038
2039 /* authorize attribute setting as kernel */
2040 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, &auio, NULL, td);
2041
2042 if ((ioflg & IO_NODELOCKED) == 0) {
2043 vn_finished_write(mp);
2044 VOP_UNLOCK(vp, 0);
2045 }
2046
2047 return (error);
2048 }
2049
2050 int
2051 vn_extattr_rm(struct vnode *vp, int ioflg, int attrnamespace,
2052 const char *attrname, struct thread *td)
2053 {
2054 struct mount *mp;
2055 int error;
2056
2057 if ((ioflg & IO_NODELOCKED) == 0) {
2058 if ((error = vn_start_write(vp, &mp, V_WAIT)) != 0)
2059 return (error);
2060 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2061 }
2062
2063 ASSERT_VOP_LOCKED(vp, "IO_NODELOCKED with no vp lock held");
2064
2065 /* authorize attribute removal as kernel */
2066 error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NULL, td);
2067 if (error == EOPNOTSUPP)
2068 error = VOP_SETEXTATTR(vp, attrnamespace, attrname, NULL,
2069 NULL, td);
2070
2071 if ((ioflg & IO_NODELOCKED) == 0) {
2072 vn_finished_write(mp);
2073 VOP_UNLOCK(vp, 0);
2074 }
2075
2076 return (error);
2077 }
2078
2079 static int
2080 vn_get_ino_alloc_vget(struct mount *mp, void *arg, int lkflags,
2081 struct vnode **rvp)
2082 {
2083
2084 return (VFS_VGET(mp, *(ino_t *)arg, lkflags, rvp));
2085 }
2086
2087 int
2088 vn_vget_ino(struct vnode *vp, ino_t ino, int lkflags, struct vnode **rvp)
2089 {
2090
2091 return (vn_vget_ino_gen(vp, vn_get_ino_alloc_vget, &ino,
2092 lkflags, rvp));
2093 }
2094
2095 int
2096 vn_vget_ino_gen(struct vnode *vp, vn_get_ino_t alloc, void *alloc_arg,
2097 int lkflags, struct vnode **rvp)
2098 {
2099 struct mount *mp;
2100 int ltype, error;
2101
2102 ASSERT_VOP_LOCKED(vp, "vn_vget_ino_get");
2103 mp = vp->v_mount;
2104 ltype = VOP_ISLOCKED(vp);
2105 KASSERT(ltype == LK_EXCLUSIVE || ltype == LK_SHARED,
2106 ("vn_vget_ino: vp not locked"));
2107 error = vfs_busy(mp, MBF_NOWAIT);
2108 if (error != 0) {
2109 vfs_ref(mp);
2110 VOP_UNLOCK(vp, 0);
2111 error = vfs_busy(mp, 0);
2112 vn_lock(vp, ltype | LK_RETRY);
2113 vfs_rel(mp);
2114 if (error != 0)
2115 return (ENOENT);
2116 if (vp->v_iflag & VI_DOOMED) {
2117 vfs_unbusy(mp);
2118 return (ENOENT);
2119 }
2120 }
2121 VOP_UNLOCK(vp, 0);
2122 error = alloc(mp, alloc_arg, lkflags, rvp);
2123 vfs_unbusy(mp);
2124 if (*rvp != vp)
2125 vn_lock(vp, ltype | LK_RETRY);
2126 if (vp->v_iflag & VI_DOOMED) {
2127 if (error == 0) {
2128 if (*rvp == vp)
2129 vunref(vp);
2130 else
2131 vput(*rvp);
2132 }
2133 error = ENOENT;
2134 }
2135 return (error);
2136 }
2137
2138 int
2139 vn_rlimit_fsize(const struct vnode *vp, const struct uio *uio,
2140 const struct thread *td)
2141 {
2142
2143 if (vp->v_type != VREG || td == NULL)
2144 return (0);
2145 PROC_LOCK(td->td_proc);
2146 if ((uoff_t)uio->uio_offset + uio->uio_resid >
2147 lim_cur(td->td_proc, RLIMIT_FSIZE)) {
2148 kern_psignal(td->td_proc, SIGXFSZ);
2149 PROC_UNLOCK(td->td_proc);
2150 return (EFBIG);
2151 }
2152 PROC_UNLOCK(td->td_proc);
2153 return (0);
2154 }
2155
2156 int
2157 vn_chmod(struct file *fp, mode_t mode, struct ucred *active_cred,
2158 struct thread *td)
2159 {
2160 struct vnode *vp;
2161
2162 vp = fp->f_vnode;
2163 #ifdef AUDIT
2164 vn_lock(vp, LK_SHARED | LK_RETRY);
2165 AUDIT_ARG_VNODE1(vp);
2166 VOP_UNLOCK(vp, 0);
2167 #endif
2168 return (setfmode(td, active_cred, vp, mode));
2169 }
2170
2171 int
2172 vn_chown(struct file *fp, uid_t uid, gid_t gid, struct ucred *active_cred,
2173 struct thread *td)
2174 {
2175 struct vnode *vp;
2176
2177 vp = fp->f_vnode;
2178 #ifdef AUDIT
2179 vn_lock(vp, LK_SHARED | LK_RETRY);
2180 AUDIT_ARG_VNODE1(vp);
2181 VOP_UNLOCK(vp, 0);
2182 #endif
2183 return (setfown(td, active_cred, vp, uid, gid));
2184 }
2185
2186 void
2187 vn_pages_remove(struct vnode *vp, vm_pindex_t start, vm_pindex_t end)
2188 {
2189 vm_object_t object;
2190
2191 if ((object = vp->v_object) == NULL)
2192 return;
2193 VM_OBJECT_WLOCK(object);
2194 vm_object_page_remove(object, start, end, 0);
2195 VM_OBJECT_WUNLOCK(object);
2196 }
2197
2198 int
2199 vn_bmap_seekhole(struct vnode *vp, u_long cmd, off_t *off, struct ucred *cred)
2200 {
2201 struct vattr va;
2202 daddr_t bn, bnp;
2203 uint64_t bsize;
2204 off_t noff;
2205 int error;
2206
2207 KASSERT(cmd == FIOSEEKHOLE || cmd == FIOSEEKDATA,
2208 ("Wrong command %lu", cmd));
2209
2210 if (vn_lock(vp, LK_SHARED) != 0)
2211 return (EBADF);
2212 if (vp->v_type != VREG) {
2213 error = ENOTTY;
2214 goto unlock;
2215 }
2216 error = VOP_GETATTR(vp, &va, cred);
2217 if (error != 0)
2218 goto unlock;
2219 noff = *off;
2220 if (noff >= va.va_size) {
2221 error = ENXIO;
2222 goto unlock;
2223 }
2224 bsize = vp->v_mount->mnt_stat.f_iosize;
2225 for (bn = noff / bsize; noff < va.va_size; bn++, noff += bsize) {
2226 error = VOP_BMAP(vp, bn, NULL, &bnp, NULL, NULL);
2227 if (error == EOPNOTSUPP) {
2228 error = ENOTTY;
2229 goto unlock;
2230 }
2231 if ((bnp == -1 && cmd == FIOSEEKHOLE) ||
2232 (bnp != -1 && cmd == FIOSEEKDATA)) {
2233 noff = bn * bsize;
2234 if (noff < *off)
2235 noff = *off;
2236 goto unlock;
2237 }
2238 }
2239 if (noff > va.va_size)
2240 noff = va.va_size;
2241 /* noff == va.va_size. There is an implicit hole at the end of file. */
2242 if (cmd == FIOSEEKDATA)
2243 error = ENXIO;
2244 unlock:
2245 VOP_UNLOCK(vp, 0);
2246 if (error == 0)
2247 *off = noff;
2248 return (error);
2249 }
2250
2251 int
2252 vn_seek(struct file *fp, off_t offset, int whence, struct thread *td)
2253 {
2254 struct ucred *cred;
2255 struct vnode *vp;
2256 struct vattr vattr;
2257 off_t foffset, size;
2258 int error, noneg;
2259
2260 cred = td->td_ucred;
2261 vp = fp->f_vnode;
2262 foffset = foffset_lock(fp, 0);
2263 noneg = (vp->v_type != VCHR);
2264 error = 0;
2265 switch (whence) {
2266 case L_INCR:
2267 if (noneg &&
2268 (foffset < 0 ||
2269 (offset > 0 && foffset > OFF_MAX - offset))) {
2270 error = EOVERFLOW;
2271 break;
2272 }
2273 offset += foffset;
2274 break;
2275 case L_XTND:
2276 vn_lock(vp, LK_SHARED | LK_RETRY);
2277 error = VOP_GETATTR(vp, &vattr, cred);
2278 VOP_UNLOCK(vp, 0);
2279 if (error)
2280 break;
2281
2282 /*
2283 * If the file references a disk device, then fetch
2284 * the media size and use that to determine the ending
2285 * offset.
2286 */
2287 if (vattr.va_size == 0 && vp->v_type == VCHR &&
2288 fo_ioctl(fp, DIOCGMEDIASIZE, &size, cred, td) == 0)
2289 vattr.va_size = size;
2290 if (noneg &&
2291 (vattr.va_size > OFF_MAX ||
2292 (offset > 0 && vattr.va_size > OFF_MAX - offset))) {
2293 error = EOVERFLOW;
2294 break;
2295 }
2296 offset += vattr.va_size;
2297 break;
2298 case L_SET:
2299 break;
2300 case SEEK_DATA:
2301 error = fo_ioctl(fp, FIOSEEKDATA, &offset, cred, td);
2302 break;
2303 case SEEK_HOLE:
2304 error = fo_ioctl(fp, FIOSEEKHOLE, &offset, cred, td);
2305 break;
2306 default:
2307 error = EINVAL;
2308 }
2309 if (error == 0 && noneg && offset < 0)
2310 error = EINVAL;
2311 if (error != 0)
2312 goto drop;
2313 VFS_KNOTE_UNLOCKED(vp, 0);
2314 *(off_t *)(td->td_retval) = offset;
2315 drop:
2316 foffset_unlock(fp, offset, error != 0 ? FOF_NOUPDATE : 0);
2317 return (error);
2318 }
2319
2320 int
2321 vn_utimes_perm(struct vnode *vp, struct vattr *vap, struct ucred *cred,
2322 struct thread *td)
2323 {
2324 int error;
2325
2326 /*
2327 * Grant permission if the caller is the owner of the file, or
2328 * the super-user, or has ACL_WRITE_ATTRIBUTES permission on
2329 * on the file. If the time pointer is null, then write
2330 * permission on the file is also sufficient.
2331 *
2332 * From NFSv4.1, draft 21, 6.2.1.3.1, Discussion of Mask Attributes:
2333 * A user having ACL_WRITE_DATA or ACL_WRITE_ATTRIBUTES
2334 * will be allowed to set the times [..] to the current
2335 * server time.
2336 */
2337 error = VOP_ACCESSX(vp, VWRITE_ATTRIBUTES, cred, td);
2338 if (error != 0 && (vap->va_vaflags & VA_UTIMES_NULL) != 0)
2339 error = VOP_ACCESS(vp, VWRITE, cred, td);
2340 return (error);
2341 }
Cache object: 49eadf753289b4c6f31e318da58c7905
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