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