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remove unnecessary offset_t casts of 0
[unleashed.git] / kernel / fs / ufs / ufs_directio.c
blobefdc928c56b05789a66c3c921fd650f3957de16c
1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
27 /* All Rights Reserved */
28
29 /*
30 * Portions of this source code were derived from Berkeley 4.3 BSD
31 * under license from the Regents of the University of California.
32 */
33
34 #include <sys/types.h>
35 #include <sys/t_lock.h>
36 #include <sys/param.h>
37 #include <sys/time.h>
38 #include <sys/systm.h>
39 #include <sys/sysmacros.h>
40 #include <sys/resource.h>
41 #include <sys/signal.h>
42 #include <sys/cred.h>
43 #include <sys/user.h>
44 #include <sys/buf.h>
45 #include <sys/vfs.h>
46 #include <sys/vnode.h>
47 #include <sys/proc.h>
48 #include <sys/disp.h>
49 #include <sys/file.h>
50 #include <sys/fcntl.h>
51 #include <sys/flock.h>
52 #include <sys/kmem.h>
53 #include <sys/uio.h>
54 #include <sys/dnlc.h>
55 #include <sys/conf.h>
56 #include <sys/mman.h>
57 #include <sys/pathname.h>
58 #include <sys/debug.h>
59 #include <sys/vmsystm.h>
60 #include <sys/cmn_err.h>
61 #include <sys/filio.h>
62 #include <sys/atomic.h>
63
64 #include <sys/fssnap_if.h>
65 #include <sys/fs/ufs_fs.h>
66 #include <sys/fs/ufs_lockfs.h>
67 #include <sys/fs/ufs_filio.h>
68 #include <sys/fs/ufs_inode.h>
69 #include <sys/fs/ufs_fsdir.h>
70 #include <sys/fs/ufs_quota.h>
71 #include <sys/fs/ufs_trans.h>
72 #include <sys/fs/ufs_panic.h>
73 #include <sys/dirent.h> /* must be AFTER <sys/fs/fsdir.h>! */
74 #include <sys/errno.h>
75
76 #include <sys/filio.h> /* _FIOIO */
77
78 #include <vm/hat.h>
79 #include <vm/page.h>
80 #include <vm/pvn.h>
81 #include <vm/as.h>
82 #include <vm/seg.h>
83 #include <vm/seg_map.h>
84 #include <vm/seg_vn.h>
85 #include <vm/seg_kmem.h>
86 #include <vm/rm.h>
87 #include <sys/swap.h>
88 #include <sys/epm.h>
89
90 #include <sys/fs_subr.h>
91
92 static void *ufs_directio_zero_buf;
93 static int ufs_directio_zero_len = 8192;
94
95 int ufs_directio_enabled = 1; /* feature is enabled */
96
97 /*
98 * for kstats reader
99 */
100 struct ufs_directio_kstats {
101 kstat_named_t logical_reads;
102 kstat_named_t phys_reads;
103 kstat_named_t hole_reads;
104 kstat_named_t nread;
105 kstat_named_t logical_writes;
106 kstat_named_t phys_writes;
107 kstat_named_t nwritten;
108 kstat_named_t nflushes;
109 } ufs_directio_kstats = {
110 { "logical_reads", KSTAT_DATA_UINT64 },
111 { "phys_reads", KSTAT_DATA_UINT64 },
112 { "hole_reads", KSTAT_DATA_UINT64 },
113 { "nread", KSTAT_DATA_UINT64 },
114 { "logical_writes", KSTAT_DATA_UINT64 },
115 { "phys_writes", KSTAT_DATA_UINT64 },
116 { "nwritten", KSTAT_DATA_UINT64 },
117 { "nflushes", KSTAT_DATA_UINT64 },
118 };
119
120 kstat_t *ufs_directio_kstatsp;
121
122 /*
123 * use kmem_cache_create for direct-physio buffers. This has shown
124 * a better cache distribution compared to buffers on the
125 * stack. It also avoids semaphore construction/deconstruction
126 * per request
127 */
128 struct directio_buf {
129 struct directio_buf *next;
130 char *addr;
131 size_t nbytes;
132 struct buf buf;
133 };
134 static struct kmem_cache *directio_buf_cache;
135
136
137 /* ARGSUSED */
138 static int
139 directio_buf_constructor(void *dbp, void *cdrarg, int kmflags)
140 {
141 bioinit((struct buf *)&((struct directio_buf *)dbp)->buf);
142 return (0);
143 }
144
145 /* ARGSUSED */
146 static void
147 directio_buf_destructor(void *dbp, void *cdrarg)
148 {
149 biofini((struct buf *)&((struct directio_buf *)dbp)->buf);
150 }
151
152 void
153 directio_bufs_init(void)
154 {
155 directio_buf_cache = kmem_cache_create("directio_buf_cache",
156 sizeof (struct directio_buf), 0,
157 directio_buf_constructor, directio_buf_destructor,
158 NULL, NULL, NULL, 0);
159 }
160
161 void
162 ufs_directio_init(void)
163 {
164 /*
165 * kstats
166 */
167 ufs_directio_kstatsp = kstat_create("ufs", 0,
168 "directio", "ufs", KSTAT_TYPE_NAMED,
169 sizeof (ufs_directio_kstats) / sizeof (kstat_named_t),
170 KSTAT_FLAG_VIRTUAL | KSTAT_FLAG_WRITABLE);
171 if (ufs_directio_kstatsp) {
172 ufs_directio_kstatsp->ks_data = (void *)&ufs_directio_kstats;
173 kstat_install(ufs_directio_kstatsp);
174 }
175 /*
176 * kzero is broken so we have to use a private buf of zeroes
177 */
178 ufs_directio_zero_buf = kmem_zalloc(ufs_directio_zero_len, KM_SLEEP);
179 directio_bufs_init();
180 }
181
182 /*
183 * Wait for the first direct IO operation to finish
184 */
185 static int
186 directio_wait_one(struct directio_buf *dbp, long *bytes_iop)
187 {
188 buf_t *bp;
189 int error;
190
191 /*
192 * Wait for IO to finish
193 */
194 bp = &dbp->buf;
195 error = biowait(bp);
196
197 /*
198 * bytes_io will be used to figure out a resid
199 * for the caller. The resid is approximated by reporting
200 * the bytes following the first failed IO as the residual.
201 *
202 * I am cautious about using b_resid because I
203 * am not sure how well the disk drivers maintain it.
204 */
205 if (error)
206 if (bp->b_resid)
207 *bytes_iop = bp->b_bcount - bp->b_resid;
208 else
209 *bytes_iop = 0;
210 else
211 *bytes_iop += bp->b_bcount;
212 /*
213 * Release direct IO resources
214 */
215 bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_SHADOW);
216 kmem_cache_free(directio_buf_cache, dbp);
217 return (error);
218 }
219
220 /*
221 * Wait for all of the direct IO operations to finish
222 */
223
224 uint32_t ufs_directio_drop_kpri = 0; /* enable kpri hack */
225
226 static int
227 directio_wait(struct directio_buf *tail, long *bytes_iop)
228 {
229 int error = 0, newerror;
230 struct directio_buf *dbp;
231 uint_t kpri_req_save;
232
233 /*
234 * The linked list of directio buf structures is maintained
235 * in reverse order (tail->last request->penultimate request->...)
236 */
237 /*
238 * This is the k_pri_req hack. Large numbers of threads
239 * sleeping with kernel priority will cause scheduler thrashing
240 * on an MP machine. This can be seen running Oracle using
241 * directio to ufs files. Sleep at normal priority here to
242 * more closely mimic physio to a device partition. This
243 * workaround is disabled by default as a niced thread could
244 * be starved from running while holding i_rwlock and i_contents.
245 */
246 if (ufs_directio_drop_kpri) {
247 kpri_req_save = curthread->t_kpri_req;
248 curthread->t_kpri_req = 0;
249 }
250 while ((dbp = tail) != NULL) {
251 tail = dbp->next;
252 newerror = directio_wait_one(dbp, bytes_iop);
253 if (error == 0)
254 error = newerror;
255 }
256 if (ufs_directio_drop_kpri)
257 curthread->t_kpri_req = kpri_req_save;
258 return (error);
259 }
260 /*
261 * Initiate direct IO request
262 */
263 static void
264 directio_start(struct ufsvfs *ufsvfsp, struct inode *ip, size_t nbytes,
265 offset_t offset, char *addr, enum seg_rw rw, struct proc *procp,
266 struct directio_buf **tailp, page_t **pplist)
267 {
268 buf_t *bp;
269 struct directio_buf *dbp;
270
271 /*
272 * Allocate a directio buf header
273 * Note - list is maintained in reverse order.
274 * directio_wait_one() depends on this fact when
275 * adjusting the ``bytes_io'' param. bytes_io
276 * is used to compute a residual in the case of error.
277 */
278 dbp = kmem_cache_alloc(directio_buf_cache, KM_SLEEP);
279 dbp->next = *tailp;
280 *tailp = dbp;
281
282 /*
283 * Initialize buf header
284 */
285 dbp->addr = addr;
286 dbp->nbytes = nbytes;
287 bp = &dbp->buf;
288 bp->b_edev = ip->i_dev;
289 bp->b_lblkno = btodt(offset);
290 bp->b_bcount = nbytes;
291 bp->b_un.b_addr = addr;
292 bp->b_proc = procp;
293 bp->b_file = ip->i_vnode;
294
295 /*
296 * Note that S_WRITE implies B_READ and vice versa: a read(2)
297 * will B_READ data from the filesystem and S_WRITE it into
298 * the user's buffer; a write(2) will S_READ data from the
299 * user's buffer and B_WRITE it to the filesystem.
300 */
301 if (rw == S_WRITE) {
302 bp->b_flags = B_BUSY | B_PHYS | B_READ;
303 ufs_directio_kstats.phys_reads.value.ui64++;
304 ufs_directio_kstats.nread.value.ui64 += nbytes;
305 } else {
306 bp->b_flags = B_BUSY | B_PHYS | B_WRITE;
307 ufs_directio_kstats.phys_writes.value.ui64++;
308 ufs_directio_kstats.nwritten.value.ui64 += nbytes;
309 }
310 bp->b_shadow = pplist;
311 if (pplist != NULL)
312 bp->b_flags |= B_SHADOW;
313
314 /*
315 * Issue I/O request.
316 */
317 ufsvfsp->vfs_iotstamp = ddi_get_lbolt();
318 if (ufsvfsp->vfs_snapshot)
319 fssnap_strategy(&ufsvfsp->vfs_snapshot, bp);
320 else
321 (void) bdev_strategy(bp);
322
323 if (rw == S_WRITE)
324 lwp_stat_update(LWP_STAT_OUBLK, 1);
325 else
326 lwp_stat_update(LWP_STAT_INBLK, 1);
327
328 }
329
330 uint32_t ufs_shared_writes; /* writes done w/ lock shared */
331 uint32_t ufs_cur_writes; /* # concurrent writes */
332 uint32_t ufs_maxcur_writes; /* high water concurrent writes */
333 uint32_t ufs_posix_hits; /* writes done /w lock excl. */
334
335 /*
336 * Force POSIX syncronous data integrity on all writes for testing.
337 */
338 uint32_t ufs_force_posix_sdi = 0;
339
340 /*
341 * Direct Write
342 */
343
344 int
345 ufs_directio_write(struct inode *ip, uio_t *arg_uio, int ioflag, int rewrite,
346 cred_t *cr, int *statusp)
347 {
348 long resid, bytes_written;
349 uoff_t size, uoff;
350 uio_t *uio = arg_uio;
351 rlim64_t limit = uio->uio_llimit;
352 int on, n, error, newerror, len, has_holes;
353 daddr_t bn;
354 size_t nbytes;
355 struct fs *fs;
356 vnode_t *vp;
357 iovec_t *iov;
358 struct ufsvfs *ufsvfsp = ip->i_ufsvfs;
359 struct proc *procp;
360 struct as *as;
361 struct directio_buf *tail;
362 int exclusive, ncur, bmap_peek;
363 uio_t copy_uio;
364 iovec_t copy_iov;
365 char *copy_base;
366 long copy_resid;
367
368 /*
369 * assume that directio isn't possible (normal case)
370 */
371 *statusp = DIRECTIO_FAILURE;
372
373 /*
374 * Don't go direct
375 */
376 if (ufs_directio_enabled == 0)
377 return (0);
378
379 /*
380 * mapped file; nevermind
381 */
382 if (ip->i_mapcnt)
383 return (0);
384
385 /*
386 * CAN WE DO DIRECT IO?
387 */
388 uoff = uio->uio_loffset;
389 resid = uio->uio_resid;
390
391 /*
392 * beyond limit
393 */
394 if (uoff + resid > limit)
395 return (0);
396
397 /*
398 * must be sector aligned
399 */
400 if ((uoff & (uoff_t)(DEV_BSIZE - 1)) || (resid & (DEV_BSIZE - 1)))
401 return (0);
402
403 /*
404 * SHOULD WE DO DIRECT IO?
405 */
406 size = ip->i_size;
407 has_holes = -1;
408
409 /*
410 * only on regular files; no metadata
411 */
412 if (((ip->i_mode & IFMT) != IFREG) || ip->i_ufsvfs->vfs_qinod == ip)
413 return (0);
414
415 /*
416 * Synchronous, allocating writes run very slow in Direct-Mode
417 * XXX - can be fixed with bmap_write changes for large writes!!!
418 * XXX - can be fixed for updates to "almost-full" files
419 * XXX - WARNING - system hangs if bmap_write() has to
420 * allocate lots of pages since pageout
421 * suspends on locked inode
422 */
423 if (!rewrite && (ip->i_flag & ISYNC)) {
424 if ((uoff + resid) > size)
425 return (0);
426 has_holes = bmap_has_holes(ip);
427 if (has_holes)
428 return (0);
429 }
430
431 /*
432 * Each iovec must be short aligned and sector aligned. If
433 * one is not, then kmem_alloc a new buffer and copy all of
434 * the smaller buffers into the new buffer. This new
435 * buffer will be short aligned and sector aligned.
436 */
437 iov = uio->uio_iov;
438 nbytes = uio->uio_iovcnt;
439 while (nbytes--) {
440 if (((uint_t)iov->iov_len & (DEV_BSIZE - 1)) != 0 ||
441 (intptr_t)(iov->iov_base) & 1) {
442 copy_resid = uio->uio_resid;
443 copy_base = kmem_alloc(copy_resid, KM_NOSLEEP);
444 if (copy_base == NULL)
445 return (0);
446 copy_iov.iov_base = copy_base;
447 copy_iov.iov_len = copy_resid;
448 copy_uio.uio_iov = &copy_iov;
449 copy_uio.uio_iovcnt = 1;
450 copy_uio.uio_segflg = UIO_SYSSPACE;
451 copy_uio.uio_extflg = UIO_COPY_DEFAULT;
452 copy_uio.uio_loffset = uio->uio_loffset;
453 copy_uio.uio_resid = uio->uio_resid;
454 copy_uio.uio_llimit = uio->uio_llimit;
455 error = uiomove(copy_base, copy_resid, UIO_WRITE, uio);
456 if (error) {
457 kmem_free(copy_base, copy_resid);
458 return (0);
459 }
460 uio = &copy_uio;
461 break;
462 }
463 iov++;
464 }
465
466 /*
467 * From here on down, all error exits must go to errout and
468 * not simply return a 0.
469 */
470
471 /*
472 * DIRECTIO
473 */
474
475 fs = ip->i_fs;
476
477 /*
478 * POSIX check. If attempting a concurrent re-write, make sure
479 * that this will be a single request to the driver to meet
480 * POSIX synchronous data integrity requirements.
481 */
482 bmap_peek = 0;
483 if (rewrite && ((ioflag & FDSYNC) || ufs_force_posix_sdi)) {
484 int upgrade = 0;
485
486 /* check easy conditions first */
487 if (uio->uio_iovcnt != 1 || resid > ufsvfsp->vfs_ioclustsz) {
488 upgrade = 1;
489 } else {
490 /* now look for contiguous allocation */
491 len = (ssize_t)blkroundup(fs, resid);
492 error = bmap_read(ip, uoff, &bn, &len);
493 if (error || bn == UFS_HOLE || len == 0)
494 goto errout;
495 /* save a call to bmap_read later */
496 bmap_peek = 1;
497 if (len < resid)
498 upgrade = 1;
499 }
500 if (upgrade) {
501 rw_exit(&ip->i_contents);
502 rw_enter(&ip->i_contents, RW_WRITER);
503 ufs_posix_hits++;
504 }
505 }
506
507
508 /*
509 * allocate space
510 */
511
512 /*
513 * If attempting a re-write, there is no allocation to do.
514 * bmap_write would trip an ASSERT if i_contents is held shared.
515 */
516 if (rewrite)
517 goto skip_alloc;
518
519 do {
520 on = (int)blkoff(fs, uoff);
521 n = (int)MIN(fs->fs_bsize - on, resid);
522 if ((uoff + n) > ip->i_size) {
523 error = bmap_write(ip, uoff, (int)(on + n),
524 (int)(uoff & (offset_t)MAXBOFFSET) == 0,
525 NULL, cr);
526 /* Caller is responsible for updating i_seq if needed */
527 if (error)
528 break;
529 ip->i_size = uoff + n;
530 ip->i_flag |= IATTCHG;
531 } else if (n == MAXBSIZE) {
532 error = bmap_write(ip, uoff, (int)(on + n),
533 BI_ALLOC_ONLY, NULL, cr);
534 /* Caller is responsible for updating i_seq if needed */
535 } else {
536 if (has_holes < 0)
537 has_holes = bmap_has_holes(ip);
538 if (has_holes) {
539 uint_t blk_size;
540 uoff_t offset;
541
542 offset = uoff & (offset_t)fs->fs_bmask;
543 blk_size = (int)blksize(fs, ip,
544 (daddr_t)lblkno(fs, offset));
545 error = bmap_write(ip, uoff, blk_size,
546 BI_NORMAL, NULL, cr);
547 /*
548 * Caller is responsible for updating
549 * i_seq if needed
550 */
551 } else
552 error = 0;
553 }
554 if (error)
555 break;
556 uoff += n;
557 resid -= n;
558 /*
559 * if file has grown larger than 2GB, set flag
560 * in superblock if not already set
561 */
562 if ((ip->i_size > MAXOFF32_T) &&
563 !(fs->fs_flags & FSLARGEFILES)) {
564 ASSERT(ufsvfsp->vfs_lfflags & UFS_LARGEFILES);
565 mutex_enter(&ufsvfsp->vfs_lock);
566 fs->fs_flags |= FSLARGEFILES;
567 ufs_sbwrite(ufsvfsp);
568 mutex_exit(&ufsvfsp->vfs_lock);
569 }
570 } while (resid);
571
572 if (error) {
573 /*
574 * restore original state
575 */
576 if (resid) {
577 if (size == ip->i_size)
578 goto errout;
579 (void) ufs_itrunc(ip, size, 0, cr);
580 }
581 /*
582 * try non-directio path
583 */
584 goto errout;
585 }
586 skip_alloc:
587
588 /*
589 * get rid of cached pages
590 */
591 vp = ITOV(ip);
592 exclusive = rw_write_held(&ip->i_contents);
593 if (vn_has_cached_data(vp)) {
594 if (!exclusive) {
595 /*
596 * Still holding i_rwlock, so no allocations
597 * can happen after dropping contents.
598 */
599 rw_exit(&ip->i_contents);
600 rw_enter(&ip->i_contents, RW_WRITER);
601 }
602 (void) fop_putpage(vp, 0, (size_t)0,
603 B_INVAL, cr, NULL);
604 if (vn_has_cached_data(vp))
605 goto errout;
606 if (!exclusive)
607 rw_downgrade(&ip->i_contents);
608 ufs_directio_kstats.nflushes.value.ui64++;
609 }
610
611 /*
612 * Direct Writes
613 */
614
615 if (!exclusive) {
616 ufs_shared_writes++;
617 ncur = atomic_inc_32_nv(&ufs_cur_writes);
618 if (ncur > ufs_maxcur_writes)
619 ufs_maxcur_writes = ncur;
620 }
621
622 /*
623 * proc and as are for VM operations in directio_start()
624 */
625 if (uio->uio_segflg == UIO_USERSPACE) {
626 procp = ttoproc(curthread);
627 as = procp->p_as;
628 } else {
629 procp = NULL;
630 as = &kas;
631 }
632 *statusp = DIRECTIO_SUCCESS;
633 error = 0;
634 newerror = 0;
635 resid = uio->uio_resid;
636 bytes_written = 0;
637 ufs_directio_kstats.logical_writes.value.ui64++;
638 while (error == 0 && newerror == 0 && resid && uio->uio_iovcnt) {
639 size_t pglck_len, pglck_size;
640 caddr_t pglck_base;
641 page_t **pplist, **spplist;
642
643 tail = NULL;
644
645 /*
646 * Adjust number of bytes
647 */
648 iov = uio->uio_iov;
649 pglck_len = (size_t)MIN(iov->iov_len, resid);
650 pglck_base = iov->iov_base;
651 if (pglck_len == 0) {
652 uio->uio_iov++;
653 uio->uio_iovcnt--;
654 continue;
655 }
656
657 /*
658 * Try to Lock down the largest chunck of pages possible.
659 */
660 pglck_len = (size_t)MIN(pglck_len, ufsvfsp->vfs_ioclustsz);
661 error = as_pagelock(as, &pplist, pglck_base, pglck_len, S_READ);
662
663 if (error)
664 break;
665
666 pglck_size = pglck_len;
667 while (pglck_len) {
668
669 nbytes = pglck_len;
670 uoff = uio->uio_loffset;
671
672 if (!bmap_peek) {
673
674 /*
675 * Re-adjust number of bytes to contiguous
676 * range. May have already called bmap_read
677 * in the case of a concurrent rewrite.
678 */
679 len = (ssize_t)blkroundup(fs, nbytes);
680 error = bmap_read(ip, uoff, &bn, &len);
681 if (error)
682 break;
683 if (bn == UFS_HOLE || len == 0)
684 break;
685 }
686 nbytes = (size_t)MIN(nbytes, len);
687 bmap_peek = 0;
688
689 /*
690 * Get the pagelist pointer for this offset to be
691 * passed to directio_start.
692 */
693
694 if (pplist != NULL)
695 spplist = pplist +
696 btop((uintptr_t)iov->iov_base -
697 ((uintptr_t)pglck_base & PAGEMASK));
698 else
699 spplist = NULL;
700
701 /*
702 * Kick off the direct write requests
703 */
704 directio_start(ufsvfsp, ip, nbytes, ldbtob(bn),
705 iov->iov_base, S_READ, procp, &tail, spplist);
706
707 /*
708 * Adjust pointers and counters
709 */
710 iov->iov_len -= nbytes;
711 iov->iov_base += nbytes;
712 uio->uio_loffset += nbytes;
713 resid -= nbytes;
714 pglck_len -= nbytes;
715 }
716
717 /*
718 * Wait for outstanding requests
719 */
720 newerror = directio_wait(tail, &bytes_written);
721
722 /*
723 * Release VM resources
724 */
725 as_pageunlock(as, pplist, pglck_base, pglck_size, S_READ);
726
727 }
728
729 if (!exclusive) {
730 atomic_dec_32(&ufs_cur_writes);
731 /*
732 * If this write was done shared, readers may
733 * have pulled in unmodified pages. Get rid of
734 * these potentially stale pages.
735 */
736 if (vn_has_cached_data(vp)) {
737 rw_exit(&ip->i_contents);
738 rw_enter(&ip->i_contents, RW_WRITER);
739 (void) fop_putpage(vp, 0, (size_t)0,
740 B_INVAL, cr, NULL);
741 ufs_directio_kstats.nflushes.value.ui64++;
742 rw_downgrade(&ip->i_contents);
743 }
744 }
745
746 /*
747 * If error, adjust resid to begin at the first
748 * un-writable byte.
749 */
750 if (error == 0)
751 error = newerror;
752 if (error)
753 resid = uio->uio_resid - bytes_written;
754 arg_uio->uio_resid = resid;
755
756 if (!rewrite) {
757 ip->i_flag |= IUPD | ICHG;
758 /* Caller will update i_seq */
759 TRANS_INODE(ip->i_ufsvfs, ip);
760 }
761 /*
762 * If there is a residual; adjust the EOF if necessary
763 */
764 if (resid) {
765 if (size != ip->i_size) {
766 if (uio->uio_loffset > size)
767 size = uio->uio_loffset;
768 (void) ufs_itrunc(ip, size, 0, cr);
769 }
770 }
771
772 if (uio == &copy_uio)
773 kmem_free(copy_base, copy_resid);
774
775 return (error);
776
777 errout:
778 if (uio == &copy_uio)
779 kmem_free(copy_base, copy_resid);
780
781 return (0);
782 }
783 /*
784 * Direct read of a hole
785 */
786 static int
787 directio_hole(struct uio *uio, size_t nbytes)
788 {
789 int error = 0, nzero;
790 uio_t phys_uio;
791 iovec_t phys_iov;
792
793 ufs_directio_kstats.hole_reads.value.ui64++;
794 ufs_directio_kstats.nread.value.ui64 += nbytes;
795
796 phys_iov.iov_base = uio->uio_iov->iov_base;
797 phys_iov.iov_len = nbytes;
798
799 phys_uio.uio_iov = &phys_iov;
800 phys_uio.uio_iovcnt = 1;
801 phys_uio.uio_resid = phys_iov.iov_len;
802 phys_uio.uio_segflg = uio->uio_segflg;
803 phys_uio.uio_extflg = uio->uio_extflg;
804 while (error == 0 && phys_uio.uio_resid) {
805 nzero = (int)MIN(phys_iov.iov_len, ufs_directio_zero_len);
806 error = uiomove(ufs_directio_zero_buf, nzero, UIO_READ,
807 &phys_uio);
808 }
809 return (error);
810 }
811
812 /*
813 * Direct Read
814 */
815 int
816 ufs_directio_read(struct inode *ip, uio_t *uio, cred_t *cr, int *statusp)
817 {
818 ssize_t resid, bytes_read;
819 uoff_t size, uoff;
820 int error, newerror, len;
821 size_t nbytes;
822 struct fs *fs;
823 vnode_t *vp;
824 daddr_t bn;
825 iovec_t *iov;
826 struct ufsvfs *ufsvfsp = ip->i_ufsvfs;
827 struct proc *procp;
828 struct as *as;
829 struct directio_buf *tail;
830
831 /*
832 * assume that directio isn't possible (normal case)
833 */
834 *statusp = DIRECTIO_FAILURE;
835
836 /*
837 * Don't go direct
838 */
839 if (ufs_directio_enabled == 0)
840 return (0);
841
842 /*
843 * mapped file; nevermind
844 */
845 if (ip->i_mapcnt)
846 return (0);
847
848 /*
849 * CAN WE DO DIRECT IO?
850 */
851 /*
852 * must be sector aligned
853 */
854 uoff = uio->uio_loffset;
855 resid = uio->uio_resid;
856 if ((uoff & (uoff_t)(DEV_BSIZE - 1)) || (resid & (DEV_BSIZE - 1)))
857 return (0);
858 /*
859 * must be short aligned and sector aligned
860 */
861 iov = uio->uio_iov;
862 nbytes = uio->uio_iovcnt;
863 while (nbytes--) {
864 if (((size_t)iov->iov_len & (DEV_BSIZE - 1)) != 0)
865 return (0);
866 if ((intptr_t)(iov++->iov_base) & 1)
867 return (0);
868 }
869
870 /*
871 * DIRECTIO
872 */
873 fs = ip->i_fs;
874
875 /*
876 * don't read past EOF
877 */
878 size = ip->i_size;
879
880 /*
881 * The file offset is past EOF so bail out here; we don't want
882 * to update uio_resid and make it look like we read something.
883 * We say that direct I/O was a success to avoid having rdip()
884 * go through the same "read past EOF logic".
885 */
886 if (uoff >= size) {
887 *statusp = DIRECTIO_SUCCESS;
888 return (0);
889 }
890
891 /*
892 * The read would extend past EOF so make it smaller.
893 */
894 if ((uoff + resid) > size) {
895 resid = size - uoff;
896 /*
897 * recheck sector alignment
898 */
899 if (resid & (DEV_BSIZE - 1))
900 return (0);
901 }
902
903 /*
904 * At this point, we know there is some real work to do.
905 */
906 ASSERT(resid);
907
908 /*
909 * get rid of cached pages
910 */
911 vp = ITOV(ip);
912 if (vn_has_cached_data(vp)) {
913 rw_exit(&ip->i_contents);
914 rw_enter(&ip->i_contents, RW_WRITER);
915 (void) fop_putpage(vp, 0, (size_t)0,
916 B_INVAL, cr, NULL);
917 if (vn_has_cached_data(vp))
918 return (0);
919 rw_downgrade(&ip->i_contents);
920 ufs_directio_kstats.nflushes.value.ui64++;
921 }
922 /*
923 * Direct Reads
924 */
925
926 /*
927 * proc and as are for VM operations in directio_start()
928 */
929 if (uio->uio_segflg == UIO_USERSPACE) {
930 procp = ttoproc(curthread);
931 as = procp->p_as;
932 } else {
933 procp = NULL;
934 as = &kas;
935 }
936
937 *statusp = DIRECTIO_SUCCESS;
938 error = 0;
939 newerror = 0;
940 bytes_read = 0;
941 ufs_directio_kstats.logical_reads.value.ui64++;
942 while (error == 0 && newerror == 0 && resid && uio->uio_iovcnt) {
943 size_t pglck_len, pglck_size;
944 caddr_t pglck_base;
945 page_t **pplist, **spplist;
946
947 tail = NULL;
948
949 /*
950 * Adjust number of bytes
951 */
952 iov = uio->uio_iov;
953 pglck_len = (size_t)MIN(iov->iov_len, resid);
954 pglck_base = iov->iov_base;
955 if (pglck_len == 0) {
956 uio->uio_iov++;
957 uio->uio_iovcnt--;
958 continue;
959 }
960
961 /*
962 * Try to Lock down the largest chunck of pages possible.
963 */
964 pglck_len = (size_t)MIN(pglck_len, ufsvfsp->vfs_ioclustsz);
965 error = as_pagelock(as, &pplist, pglck_base,
966 pglck_len, S_WRITE);
967
968 if (error)
969 break;
970
971 pglck_size = pglck_len;
972 while (pglck_len) {
973
974 nbytes = pglck_len;
975 uoff = uio->uio_loffset;
976
977 /*
978 * Re-adjust number of bytes to contiguous range
979 */
980 len = (ssize_t)blkroundup(fs, nbytes);
981 error = bmap_read(ip, uoff, &bn, &len);
982 if (error)
983 break;
984
985 if (bn == UFS_HOLE) {
986 nbytes = (size_t)MIN(fs->fs_bsize -
987 (long)blkoff(fs, uoff), nbytes);
988 error = directio_hole(uio, nbytes);
989 /*
990 * Hole reads are not added to the list
991 * processed by directio_wait() below so
992 * account for bytes read here.
993 */
994 if (!error)
995 bytes_read += nbytes;
996 } else {
997 nbytes = (size_t)MIN(nbytes, len);
998
999 /*
1000 * Get the pagelist pointer for this offset
1001 * to be passed to directio_start.
1002 */
1003 if (pplist != NULL)
1004 spplist = pplist +
1005 btop((uintptr_t)iov->iov_base -
1006 ((uintptr_t)pglck_base & PAGEMASK));
1007 else
1008 spplist = NULL;
1009
1010 /*
1011 * Kick off the direct read requests
1012 */
1013 directio_start(ufsvfsp, ip, nbytes,
1014 ldbtob(bn), iov->iov_base,
1015 S_WRITE, procp, &tail, spplist);
1016 }
1017
1018 if (error)
1019 break;
1020
1021 /*
1022 * Adjust pointers and counters
1023 */
1024 iov->iov_len -= nbytes;
1025 iov->iov_base += nbytes;
1026 uio->uio_loffset += nbytes;
1027 resid -= nbytes;
1028 pglck_len -= nbytes;
1029 }
1030
1031 /*
1032 * Wait for outstanding requests
1033 */
1034 newerror = directio_wait(tail, &bytes_read);
1035 /*
1036 * Release VM resources
1037 */
1038 as_pageunlock(as, pplist, pglck_base, pglck_size, S_WRITE);
1039
1040 }
1041
1042 /*
1043 * If error, adjust resid to begin at the first
1044 * un-read byte.
1045 */
1046 if (error == 0)
1047 error = newerror;
1048 uio->uio_resid -= bytes_read;
1049 return (error);
1050 }
Unleashed OS