FreeBSD/Linux Kernel Cross Reference
sys/fs/fuse/fuse_io.c
1 /*
2 * Copyright (c) 2007-2009 Google Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 * * Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * * Redistributions in binary form must reproduce the above
12 * copyright notice, this list of conditions and the following disclaimer
13 * in the documentation and/or other materials provided with the
14 * distribution.
15 * * Neither the name of Google Inc. nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 *
31 * Copyright (C) 2005 Csaba Henk.
32 * All rights reserved.
33 *
34 * Redistribution and use in source and binary forms, with or without
35 * modification, are permitted provided that the following conditions
36 * are met:
37 * 1. Redistributions of source code must retain the above copyright
38 * notice, this list of conditions and the following disclaimer.
39 * 2. Redistributions in binary form must reproduce the above copyright
40 * notice, this list of conditions and the following disclaimer in the
41 * documentation and/or other materials provided with the distribution.
42 *
43 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
44 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
46 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
47 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
49 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
50 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
51 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
52 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * SUCH DAMAGE.
54 */
55
56 #include <sys/cdefs.h>
57 __FBSDID("$FreeBSD$");
58
59 #include <sys/types.h>
60 #include <sys/module.h>
61 #include <sys/systm.h>
62 #include <sys/errno.h>
63 #include <sys/param.h>
64 #include <sys/kernel.h>
65 #include <sys/conf.h>
66 #include <sys/uio.h>
67 #include <sys/malloc.h>
68 #include <sys/queue.h>
69 #include <sys/lock.h>
70 #include <sys/sx.h>
71 #include <sys/mutex.h>
72 #include <sys/rwlock.h>
73 #include <sys/proc.h>
74 #include <sys/mount.h>
75 #include <sys/vnode.h>
76 #include <sys/stat.h>
77 #include <sys/unistd.h>
78 #include <sys/filedesc.h>
79 #include <sys/file.h>
80 #include <sys/fcntl.h>
81 #include <sys/bio.h>
82 #include <sys/buf.h>
83 #include <sys/sysctl.h>
84
85 #include <vm/vm.h>
86 #include <vm/vm_extern.h>
87 #include <vm/pmap.h>
88 #include <vm/vm_map.h>
89 #include <vm/vm_page.h>
90 #include <vm/vm_object.h>
91
92 #include "fuse.h"
93 #include "fuse_file.h"
94 #include "fuse_node.h"
95 #include "fuse_internal.h"
96 #include "fuse_ipc.h"
97 #include "fuse_io.h"
98
99 #define FUSE_DEBUG_MODULE IO
100 #include "fuse_debug.h"
101
102
103 static int
104 fuse_read_directbackend(struct vnode *vp, struct uio *uio,
105 struct ucred *cred, struct fuse_filehandle *fufh);
106 static int
107 fuse_read_biobackend(struct vnode *vp, struct uio *uio,
108 struct ucred *cred, struct fuse_filehandle *fufh);
109 static int
110 fuse_write_directbackend(struct vnode *vp, struct uio *uio,
111 struct ucred *cred, struct fuse_filehandle *fufh, int ioflag);
112 static int
113 fuse_write_biobackend(struct vnode *vp, struct uio *uio,
114 struct ucred *cred, struct fuse_filehandle *fufh, int ioflag);
115
116 int
117 fuse_io_dispatch(struct vnode *vp, struct uio *uio, int ioflag,
118 struct ucred *cred)
119 {
120 struct fuse_filehandle *fufh;
121 int err, directio;
122
123 MPASS(vp->v_type == VREG || vp->v_type == VDIR);
124
125 err = fuse_filehandle_getrw(vp,
126 (uio->uio_rw == UIO_READ) ? FUFH_RDONLY : FUFH_WRONLY, &fufh);
127 if (err) {
128 printf("FUSE: io dispatch: filehandles are closed\n");
129 return err;
130 }
131 /*
132 * Ideally, when the daemon asks for direct io at open time, the
133 * standard file flag should be set according to this, so that would
134 * just change the default mode, which later on could be changed via
135 * fcntl(2).
136 * But this doesn't work, the O_DIRECT flag gets cleared at some point
137 * (don't know where). So to make any use of the Fuse direct_io option,
138 * we hardwire it into the file's private data (similarly to Linux,
139 * btw.).
140 */
141 directio = (ioflag & IO_DIRECT) || !fsess_opt_datacache(vnode_mount(vp));
142
143 switch (uio->uio_rw) {
144 case UIO_READ:
145 if (directio) {
146 FS_DEBUG("direct read of vnode %ju via file handle %ju\n",
147 (uintmax_t)VTOILLU(vp), (uintmax_t)fufh->fh_id);
148 err = fuse_read_directbackend(vp, uio, cred, fufh);
149 } else {
150 FS_DEBUG("buffered read of vnode %ju\n",
151 (uintmax_t)VTOILLU(vp));
152 err = fuse_read_biobackend(vp, uio, cred, fufh);
153 }
154 break;
155 case UIO_WRITE:
156 if (directio) {
157 FS_DEBUG("direct write of vnode %ju via file handle %ju\n",
158 (uintmax_t)VTOILLU(vp), (uintmax_t)fufh->fh_id);
159 err = fuse_write_directbackend(vp, uio, cred, fufh, ioflag);
160 } else {
161 FS_DEBUG("buffered write of vnode %ju\n",
162 (uintmax_t)VTOILLU(vp));
163 err = fuse_write_biobackend(vp, uio, cred, fufh, ioflag);
164 }
165 break;
166 default:
167 panic("uninterpreted mode passed to fuse_io_dispatch");
168 }
169
170 return (err);
171 }
172
173 static int
174 fuse_read_biobackend(struct vnode *vp, struct uio *uio,
175 struct ucred *cred, struct fuse_filehandle *fufh)
176 {
177 struct buf *bp;
178 daddr_t lbn;
179 int bcount;
180 int err = 0, n = 0, on = 0;
181 off_t filesize;
182
183 const int biosize = fuse_iosize(vp);
184
185 FS_DEBUG("resid=%zx offset=%jx fsize=%jx\n",
186 uio->uio_resid, uio->uio_offset, VTOFUD(vp)->filesize);
187
188 if (uio->uio_resid == 0)
189 return (0);
190 if (uio->uio_offset < 0)
191 return (EINVAL);
192
193 bcount = MIN(MAXBSIZE, biosize);
194 filesize = VTOFUD(vp)->filesize;
195
196 do {
197 if (fuse_isdeadfs(vp)) {
198 err = ENXIO;
199 break;
200 }
201 lbn = uio->uio_offset / biosize;
202 on = uio->uio_offset & (biosize - 1);
203
204 FS_DEBUG2G("biosize %d, lbn %d, on %d\n", biosize, (int)lbn, on);
205
206 /*
207 * Obtain the buffer cache block. Figure out the buffer size
208 * when we are at EOF. If we are modifying the size of the
209 * buffer based on an EOF condition we need to hold
210 * nfs_rslock() through obtaining the buffer to prevent
211 * a potential writer-appender from messing with n_size.
212 * Otherwise we may accidentally truncate the buffer and
213 * lose dirty data.
214 *
215 * Note that bcount is *not* DEV_BSIZE aligned.
216 */
217 if ((off_t)lbn * biosize >= filesize) {
218 bcount = 0;
219 } else if ((off_t)(lbn + 1) * biosize > filesize) {
220 bcount = filesize - (off_t)lbn *biosize;
221 }
222 bp = getblk(vp, lbn, bcount, PCATCH, 0, 0);
223
224 if (!bp)
225 return (EINTR);
226
227 /*
228 * If B_CACHE is not set, we must issue the read. If this
229 * fails, we return an error.
230 */
231
232 if ((bp->b_flags & B_CACHE) == 0) {
233 bp->b_iocmd = BIO_READ;
234 vfs_busy_pages(bp, 0);
235 err = fuse_io_strategy(vp, bp);
236 if (err) {
237 brelse(bp);
238 return (err);
239 }
240 }
241 /*
242 * on is the offset into the current bp. Figure out how many
243 * bytes we can copy out of the bp. Note that bcount is
244 * NOT DEV_BSIZE aligned.
245 *
246 * Then figure out how many bytes we can copy into the uio.
247 */
248
249 n = 0;
250 if (on < bcount)
251 n = MIN((unsigned)(bcount - on), uio->uio_resid);
252 if (n > 0) {
253 FS_DEBUG2G("feeding buffeater with %d bytes of buffer %p,"
254 " saying %d was asked for\n",
255 n, bp->b_data + on, n + (int)bp->b_resid);
256 err = uiomove(bp->b_data + on, n, uio);
257 }
258 brelse(bp);
259 FS_DEBUG2G("end of turn, err %d, uio->uio_resid %zd, n %d\n",
260 err, uio->uio_resid, n);
261 } while (err == 0 && uio->uio_resid > 0 && n > 0);
262
263 return (err);
264 }
265
266 static int
267 fuse_read_directbackend(struct vnode *vp, struct uio *uio,
268 struct ucred *cred, struct fuse_filehandle *fufh)
269 {
270 struct fuse_dispatcher fdi;
271 struct fuse_read_in *fri;
272 int err = 0;
273
274 if (uio->uio_resid == 0)
275 return (0);
276
277 fdisp_init(&fdi, 0);
278
279 /*
280 * XXX In "normal" case we use an intermediate kernel buffer for
281 * transmitting data from daemon's context to ours. Eventually, we should
282 * get rid of this. Anyway, if the target uio lives in sysspace (we are
283 * called from pageops), and the input data doesn't need kernel-side
284 * processing (we are not called from readdir) we can already invoke
285 * an optimized, "peer-to-peer" I/O routine.
286 */
287 while (uio->uio_resid > 0) {
288 fdi.iosize = sizeof(*fri);
289 fdisp_make_vp(&fdi, FUSE_READ, vp, uio->uio_td, cred);
290 fri = fdi.indata;
291 fri->fh = fufh->fh_id;
292 fri->offset = uio->uio_offset;
293 fri->size = MIN(uio->uio_resid,
294 fuse_get_mpdata(vp->v_mount)->max_read);
295
296 FS_DEBUG2G("fri->fh %ju, fri->offset %ju, fri->size %ju\n",
297 (uintmax_t)fri->fh, (uintmax_t)fri->offset,
298 (uintmax_t)fri->size);
299
300 if ((err = fdisp_wait_answ(&fdi)))
301 goto out;
302
303 FS_DEBUG2G("complete: got iosize=%d, requested fri.size=%zd; "
304 "resid=%zd offset=%ju\n",
305 fri->size, fdi.iosize, uio->uio_resid,
306 (uintmax_t)uio->uio_offset);
307
308 if ((err = uiomove(fdi.answ, MIN(fri->size, fdi.iosize), uio)))
309 break;
310 if (fdi.iosize < fri->size)
311 break;
312 }
313
314 out:
315 fdisp_destroy(&fdi);
316 return (err);
317 }
318
319 static int
320 fuse_write_directbackend(struct vnode *vp, struct uio *uio,
321 struct ucred *cred, struct fuse_filehandle *fufh, int ioflag)
322 {
323 struct fuse_vnode_data *fvdat = VTOFUD(vp);
324 struct fuse_write_in *fwi;
325 struct fuse_dispatcher fdi;
326 size_t chunksize;
327 int diff;
328 int err = 0;
329
330 if (uio->uio_resid == 0)
331 return (0);
332 if (ioflag & IO_APPEND)
333 uio_setoffset(uio, fvdat->filesize);
334
335 fdisp_init(&fdi, 0);
336
337 while (uio->uio_resid > 0) {
338 chunksize = MIN(uio->uio_resid,
339 fuse_get_mpdata(vp->v_mount)->max_write);
340
341 fdi.iosize = sizeof(*fwi) + chunksize;
342 fdisp_make_vp(&fdi, FUSE_WRITE, vp, uio->uio_td, cred);
343
344 fwi = fdi.indata;
345 fwi->fh = fufh->fh_id;
346 fwi->offset = uio->uio_offset;
347 fwi->size = chunksize;
348
349 if ((err = uiomove((char *)fdi.indata + sizeof(*fwi),
350 chunksize, uio)))
351 break;
352
353 if ((err = fdisp_wait_answ(&fdi)))
354 break;
355
356 diff = chunksize - ((struct fuse_write_out *)fdi.answ)->size;
357 if (diff < 0) {
358 err = EINVAL;
359 break;
360 }
361 uio->uio_resid += diff;
362 uio->uio_offset -= diff;
363 if (uio->uio_offset > fvdat->filesize)
364 fuse_vnode_setsize(vp, uio->uio_offset);
365 }
366
367 fdisp_destroy(&fdi);
368
369 return (err);
370 }
371
372 static int
373 fuse_write_biobackend(struct vnode *vp, struct uio *uio,
374 struct ucred *cred, struct fuse_filehandle *fufh, int ioflag)
375 {
376 struct fuse_vnode_data *fvdat = VTOFUD(vp);
377 struct buf *bp;
378 daddr_t lbn;
379 int bcount;
380 int n, on, err = 0;
381
382 const int biosize = fuse_iosize(vp);
383
384 KASSERT(uio->uio_rw == UIO_WRITE, ("ncl_write mode"));
385 FS_DEBUG("resid=%zx offset=%jx fsize=%jx\n",
386 uio->uio_resid, uio->uio_offset, fvdat->filesize);
387 if (vp->v_type != VREG)
388 return (EIO);
389 if (uio->uio_offset < 0)
390 return (EINVAL);
391 if (uio->uio_resid == 0)
392 return (0);
393 if (ioflag & IO_APPEND)
394 uio_setoffset(uio, fvdat->filesize);
395
396 /*
397 * Find all of this file's B_NEEDCOMMIT buffers. If our writes
398 * would exceed the local maximum per-file write commit size when
399 * combined with those, we must decide whether to flush,
400 * go synchronous, or return err. We don't bother checking
401 * IO_UNIT -- we just make all writes atomic anyway, as there's
402 * no point optimizing for something that really won't ever happen.
403 */
404 do {
405 if (fuse_isdeadfs(vp)) {
406 err = ENXIO;
407 break;
408 }
409 lbn = uio->uio_offset / biosize;
410 on = uio->uio_offset & (biosize - 1);
411 n = MIN((unsigned)(biosize - on), uio->uio_resid);
412
413 FS_DEBUG2G("lbn %ju, on %d, n %d, uio offset %ju, uio resid %zd\n",
414 (uintmax_t)lbn, on, n,
415 (uintmax_t)uio->uio_offset, uio->uio_resid);
416
417 again:
418 /*
419 * Handle direct append and file extension cases, calculate
420 * unaligned buffer size.
421 */
422 if (uio->uio_offset == fvdat->filesize && n) {
423 /*
424 * Get the buffer (in its pre-append state to maintain
425 * B_CACHE if it was previously set). Resize the
426 * nfsnode after we have locked the buffer to prevent
427 * readers from reading garbage.
428 */
429 bcount = on;
430 FS_DEBUG("getting block from OS, bcount %d\n", bcount);
431 bp = getblk(vp, lbn, bcount, PCATCH, 0, 0);
432
433 if (bp != NULL) {
434 long save;
435
436 err = fuse_vnode_setsize(vp,
437 uio->uio_offset + n);
438 if (err) {
439 brelse(bp);
440 break;
441 }
442 save = bp->b_flags & B_CACHE;
443 bcount += n;
444 allocbuf(bp, bcount);
445 bp->b_flags |= save;
446 }
447 } else {
448 /*
449 * Obtain the locked cache block first, and then
450 * adjust the file's size as appropriate.
451 */
452 bcount = on + n;
453 if ((off_t)lbn * biosize + bcount < fvdat->filesize) {
454 if ((off_t)(lbn + 1) * biosize < fvdat->filesize)
455 bcount = biosize;
456 else
457 bcount = fvdat->filesize -
458 (off_t)lbn *biosize;
459 }
460 FS_DEBUG("getting block from OS, bcount %d\n", bcount);
461 bp = getblk(vp, lbn, bcount, PCATCH, 0, 0);
462 if (bp && uio->uio_offset + n > fvdat->filesize) {
463 err = fuse_vnode_setsize(vp,
464 uio->uio_offset + n);
465 if (err) {
466 brelse(bp);
467 break;
468 }
469 }
470 }
471
472 if (!bp) {
473 err = EINTR;
474 break;
475 }
476 /*
477 * Issue a READ if B_CACHE is not set. In special-append
478 * mode, B_CACHE is based on the buffer prior to the write
479 * op and is typically set, avoiding the read. If a read
480 * is required in special append mode, the server will
481 * probably send us a short-read since we extended the file
482 * on our end, resulting in b_resid == 0 and, thusly,
483 * B_CACHE getting set.
484 *
485 * We can also avoid issuing the read if the write covers
486 * the entire buffer. We have to make sure the buffer state
487 * is reasonable in this case since we will not be initiating
488 * I/O. See the comments in kern/vfs_bio.c's getblk() for
489 * more information.
490 *
491 * B_CACHE may also be set due to the buffer being cached
492 * normally.
493 */
494
495 if (on == 0 && n == bcount) {
496 bp->b_flags |= B_CACHE;
497 bp->b_flags &= ~B_INVAL;
498 bp->b_ioflags &= ~BIO_ERROR;
499 }
500 if ((bp->b_flags & B_CACHE) == 0) {
501 bp->b_iocmd = BIO_READ;
502 vfs_busy_pages(bp, 0);
503 fuse_io_strategy(vp, bp);
504 if ((err = bp->b_error)) {
505 brelse(bp);
506 break;
507 }
508 }
509 if (bp->b_wcred == NOCRED)
510 bp->b_wcred = crhold(cred);
511
512 /*
513 * If dirtyend exceeds file size, chop it down. This should
514 * not normally occur but there is an append race where it
515 * might occur XXX, so we log it.
516 *
517 * If the chopping creates a reverse-indexed or degenerate
518 * situation with dirtyoff/end, we 0 both of them.
519 */
520
521 if (bp->b_dirtyend > bcount) {
522 FS_DEBUG("FUSE append race @%lx:%d\n",
523 (long)bp->b_blkno * biosize,
524 bp->b_dirtyend - bcount);
525 bp->b_dirtyend = bcount;
526 }
527 if (bp->b_dirtyoff >= bp->b_dirtyend)
528 bp->b_dirtyoff = bp->b_dirtyend = 0;
529
530 /*
531 * If the new write will leave a contiguous dirty
532 * area, just update the b_dirtyoff and b_dirtyend,
533 * otherwise force a write rpc of the old dirty area.
534 *
535 * While it is possible to merge discontiguous writes due to
536 * our having a B_CACHE buffer ( and thus valid read data
537 * for the hole), we don't because it could lead to
538 * significant cache coherency problems with multiple clients,
539 * especially if locking is implemented later on.
540 *
541 * as an optimization we could theoretically maintain
542 * a linked list of discontinuous areas, but we would still
543 * have to commit them separately so there isn't much
544 * advantage to it except perhaps a bit of asynchronization.
545 */
546
547 if (bp->b_dirtyend > 0 &&
548 (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
549 /*
550 * Yes, we mean it. Write out everything to "storage"
551 * immediately, without hesitation. (Apart from other
552 * reasons: the only way to know if a write is valid
553 * if its actually written out.)
554 */
555 bwrite(bp);
556 if (bp->b_error == EINTR) {
557 err = EINTR;
558 break;
559 }
560 goto again;
561 }
562 err = uiomove((char *)bp->b_data + on, n, uio);
563
564 /*
565 * Since this block is being modified, it must be written
566 * again and not just committed. Since write clustering does
567 * not work for the stage 1 data write, only the stage 2
568 * commit rpc, we have to clear B_CLUSTEROK as well.
569 */
570 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
571
572 if (err) {
573 bp->b_ioflags |= BIO_ERROR;
574 bp->b_error = err;
575 brelse(bp);
576 break;
577 }
578 /*
579 * Only update dirtyoff/dirtyend if not a degenerate
580 * condition.
581 */
582 if (n) {
583 if (bp->b_dirtyend > 0) {
584 bp->b_dirtyoff = MIN(on, bp->b_dirtyoff);
585 bp->b_dirtyend = MAX((on + n), bp->b_dirtyend);
586 } else {
587 bp->b_dirtyoff = on;
588 bp->b_dirtyend = on + n;
589 }
590 vfs_bio_set_valid(bp, on, n);
591 }
592 err = bwrite(bp);
593 if (err)
594 break;
595 } while (uio->uio_resid > 0 && n > 0);
596
597 if (fuse_sync_resize && (fvdat->flag & FN_SIZECHANGE) != 0)
598 fuse_vnode_savesize(vp, cred);
599
600 return (err);
601 }
602
603 int
604 fuse_io_strategy(struct vnode *vp, struct buf *bp)
605 {
606 struct fuse_filehandle *fufh;
607 struct fuse_vnode_data *fvdat = VTOFUD(vp);
608 struct ucred *cred;
609 struct uio *uiop;
610 struct uio uio;
611 struct iovec io;
612 int error = 0;
613
614 const int biosize = fuse_iosize(vp);
615
616 MPASS(vp->v_type == VREG || vp->v_type == VDIR);
617 MPASS(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE);
618 FS_DEBUG("inode=%ju offset=%jd resid=%ld\n",
619 (uintmax_t)VTOI(vp), (intmax_t)(((off_t)bp->b_blkno) * biosize),
620 bp->b_bcount);
621
622 error = fuse_filehandle_getrw(vp,
623 (bp->b_iocmd == BIO_READ) ? FUFH_RDONLY : FUFH_WRONLY, &fufh);
624 if (error) {
625 printf("FUSE: strategy: filehandles are closed\n");
626 bp->b_ioflags |= BIO_ERROR;
627 bp->b_error = error;
628 return (error);
629 }
630 cred = bp->b_iocmd == BIO_READ ? bp->b_rcred : bp->b_wcred;
631
632 uiop = &uio;
633 uiop->uio_iov = &io;
634 uiop->uio_iovcnt = 1;
635 uiop->uio_segflg = UIO_SYSSPACE;
636 uiop->uio_td = curthread;
637
638 /*
639 * clear BIO_ERROR and B_INVAL state prior to initiating the I/O. We
640 * do this here so we do not have to do it in all the code that
641 * calls us.
642 */
643 bp->b_flags &= ~B_INVAL;
644 bp->b_ioflags &= ~BIO_ERROR;
645
646 KASSERT(!(bp->b_flags & B_DONE),
647 ("fuse_io_strategy: bp %p already marked done", bp));
648 if (bp->b_iocmd == BIO_READ) {
649 io.iov_len = uiop->uio_resid = bp->b_bcount;
650 io.iov_base = bp->b_data;
651 uiop->uio_rw = UIO_READ;
652
653 uiop->uio_offset = ((off_t)bp->b_blkno) * biosize;
654 error = fuse_read_directbackend(vp, uiop, cred, fufh);
655
656 if ((!error && uiop->uio_resid) ||
657 (fsess_opt_brokenio(vnode_mount(vp)) && error == EIO &&
658 uiop->uio_offset < fvdat->filesize && fvdat->filesize > 0 &&
659 uiop->uio_offset >= fvdat->cached_attrs.va_size)) {
660 /*
661 * If we had a short read with no error, we must have
662 * hit a file hole. We should zero-fill the remainder.
663 * This can also occur if the server hits the file EOF.
664 *
665 * Holes used to be able to occur due to pending
666 * writes, but that is not possible any longer.
667 */
668 int nread = bp->b_bcount - uiop->uio_resid;
669 int left = uiop->uio_resid;
670
671 if (error != 0) {
672 printf("FUSE: Fix broken io: offset %ju, "
673 " resid %zd, file size %ju/%ju\n",
674 (uintmax_t)uiop->uio_offset,
675 uiop->uio_resid, fvdat->filesize,
676 fvdat->cached_attrs.va_size);
677 error = 0;
678 }
679 if (left > 0)
680 bzero((char *)bp->b_data + nread, left);
681 uiop->uio_resid = 0;
682 }
683 if (error) {
684 bp->b_ioflags |= BIO_ERROR;
685 bp->b_error = error;
686 }
687 } else {
688 /*
689 * If we only need to commit, try to commit
690 */
691 if (bp->b_flags & B_NEEDCOMMIT) {
692 FS_DEBUG("write: B_NEEDCOMMIT flags set\n");
693 }
694 /*
695 * Setup for actual write
696 */
697 if ((off_t)bp->b_blkno * biosize + bp->b_dirtyend >
698 fvdat->filesize)
699 bp->b_dirtyend = fvdat->filesize -
700 (off_t)bp->b_blkno * biosize;
701
702 if (bp->b_dirtyend > bp->b_dirtyoff) {
703 io.iov_len = uiop->uio_resid = bp->b_dirtyend
704 - bp->b_dirtyoff;
705 uiop->uio_offset = (off_t)bp->b_blkno * biosize
706 + bp->b_dirtyoff;
707 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
708 uiop->uio_rw = UIO_WRITE;
709
710 error = fuse_write_directbackend(vp, uiop, cred, fufh, 0);
711
712 if (error == EINTR || error == ETIMEDOUT
713 || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
714
715 bp->b_flags &= ~(B_INVAL | B_NOCACHE);
716 if ((bp->b_flags & B_PAGING) == 0) {
717 bdirty(bp);
718 bp->b_flags &= ~B_DONE;
719 }
720 if ((error == EINTR || error == ETIMEDOUT) &&
721 (bp->b_flags & B_ASYNC) == 0)
722 bp->b_flags |= B_EINTR;
723 } else {
724 if (error) {
725 bp->b_ioflags |= BIO_ERROR;
726 bp->b_flags |= B_INVAL;
727 bp->b_error = error;
728 }
729 bp->b_dirtyoff = bp->b_dirtyend = 0;
730 }
731 } else {
732 bp->b_resid = 0;
733 bufdone(bp);
734 return (0);
735 }
736 }
737 bp->b_resid = uiop->uio_resid;
738 bufdone(bp);
739 return (error);
740 }
741
742 int
743 fuse_io_flushbuf(struct vnode *vp, int waitfor, struct thread *td)
744 {
745 struct vop_fsync_args a = {
746 .a_vp = vp,
747 .a_waitfor = waitfor,
748 .a_td = td,
749 };
750
751 return (vop_stdfsync(&a));
752 }
753
754 /*
755 * Flush and invalidate all dirty buffers. If another process is already
756 * doing the flush, just wait for completion.
757 */
758 int
759 fuse_io_invalbuf(struct vnode *vp, struct thread *td)
760 {
761 struct fuse_vnode_data *fvdat = VTOFUD(vp);
762 int error = 0;
763
764 if (vp->v_iflag & VI_DOOMED)
765 return 0;
766
767 ASSERT_VOP_ELOCKED(vp, "fuse_io_invalbuf");
768
769 while (fvdat->flag & FN_FLUSHINPROG) {
770 struct proc *p = td->td_proc;
771
772 if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF)
773 return EIO;
774 fvdat->flag |= FN_FLUSHWANT;
775 tsleep(&fvdat->flag, PRIBIO + 2, "fusevinv", 2 * hz);
776 error = 0;
777 if (p != NULL) {
778 PROC_LOCK(p);
779 if (SIGNOTEMPTY(p->p_siglist) ||
780 SIGNOTEMPTY(td->td_siglist))
781 error = EINTR;
782 PROC_UNLOCK(p);
783 }
784 if (error == EINTR)
785 return EINTR;
786 }
787 fvdat->flag |= FN_FLUSHINPROG;
788
789 if (vp->v_bufobj.bo_object != NULL) {
790 VM_OBJECT_WLOCK(vp->v_bufobj.bo_object);
791 vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
792 VM_OBJECT_WUNLOCK(vp->v_bufobj.bo_object);
793 }
794 error = vinvalbuf(vp, V_SAVE, PCATCH, 0);
795 while (error) {
796 if (error == ERESTART || error == EINTR) {
797 fvdat->flag &= ~FN_FLUSHINPROG;
798 if (fvdat->flag & FN_FLUSHWANT) {
799 fvdat->flag &= ~FN_FLUSHWANT;
800 wakeup(&fvdat->flag);
801 }
802 return EINTR;
803 }
804 error = vinvalbuf(vp, V_SAVE, PCATCH, 0);
805 }
806 fvdat->flag &= ~FN_FLUSHINPROG;
807 if (fvdat->flag & FN_FLUSHWANT) {
808 fvdat->flag &= ~FN_FLUSHWANT;
809 wakeup(&fvdat->flag);
810 }
811 return (error);
812 }
Cache object: debbc19aa8ca0d7a5c1415d021bf82de
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