1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 2007-2009 Google Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions are 9 * met: 10 * 11 * * Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * * Redistributions in binary form must reproduce the above 14 * copyright notice, this list of conditions and the following disclaimer 15 * in the documentation and/or other materials provided with the 16 * distribution. 17 * * Neither the name of Google Inc. nor the names of its 18 * contributors may be used to endorse or promote products derived from 19 * this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 * 33 * Copyright (C) 2005 Csaba Henk. 34 * All rights reserved. 35 * 36 * Copyright (c) 2019 The FreeBSD Foundation 37 * 38 * Portions of this software were developed by BFF Storage Systems, LLC under 39 * sponsorship from the FreeBSD Foundation. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 50 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 * SUCH DAMAGE. 61 */ 62 63 #include <sys/types.h> 64 #include <sys/param.h> 65 #include <sys/module.h> 66 #include <sys/systm.h> 67 #include <sys/errno.h> 68 #include <sys/param.h> 69 #include <sys/kernel.h> 70 #include <sys/conf.h> 71 #include <sys/uio.h> 72 #include <sys/malloc.h> 73 #include <sys/queue.h> 74 #include <sys/lock.h> 75 #include <sys/sx.h> 76 #include <sys/mutex.h> 77 #include <sys/rwlock.h> 78 #include <sys/priv.h> 79 #include <sys/proc.h> 80 #include <sys/mount.h> 81 #include <sys/vnode.h> 82 #include <sys/stat.h> 83 #include <sys/unistd.h> 84 #include <sys/filedesc.h> 85 #include <sys/file.h> 86 #include <sys/fcntl.h> 87 #include <sys/bio.h> 88 #include <sys/buf.h> 89 #include <sys/sysctl.h> 90 #include <sys/vmmeter.h> 91 92 #include <vm/vm.h> 93 #include <vm/vm_extern.h> 94 #include <vm/pmap.h> 95 #include <vm/vm_map.h> 96 #include <vm/vm_page.h> 97 #include <vm/vm_object.h> 98 99 #include "fuse.h" 100 #include "fuse_file.h" 101 #include "fuse_node.h" 102 #include "fuse_internal.h" 103 #include "fuse_ipc.h" 104 #include "fuse_io.h" 105 106 /* 107 * Set in a struct buf to indicate that the write came from the buffer cache 108 * and the originating cred and pid are no longer known. 109 */ 110 #define B_FUSEFS_WRITE_CACHE B_FS_FLAG1 111 112 SDT_PROVIDER_DECLARE(fusefs); 113 /* 114 * Fuse trace probe: 115 * arg0: verbosity. Higher numbers give more verbose messages 116 * arg1: Textual message 117 */ 118 SDT_PROBE_DEFINE2(fusefs, , io, trace, "int", "char*"); 119 120 SDT_PROBE_DEFINE4(fusefs, , io, read_bio_backend_start, "int", "int", "int", "int"); 121 SDT_PROBE_DEFINE2(fusefs, , io, read_bio_backend_feed, "int", "struct buf*"); 122 SDT_PROBE_DEFINE4(fusefs, , io, read_bio_backend_end, "int", "ssize_t", "int", 123 "struct buf*"); 124 int 125 fuse_read_biobackend(struct vnode *vp, struct uio *uio, int ioflag, 126 struct ucred *cred, struct fuse_filehandle *fufh, pid_t pid) 127 { 128 struct buf *bp; 129 struct mount *mp; 130 struct fuse_data *data; 131 daddr_t lbn, nextlbn; 132 int bcount, nextsize; 133 int err, n = 0, on = 0, seqcount; 134 off_t filesize; 135 136 const int biosize = fuse_iosize(vp); 137 mp = vnode_mount(vp); 138 data = fuse_get_mpdata(mp); 139 140 if (uio->uio_offset < 0) 141 return (EINVAL); 142 143 seqcount = ioflag >> IO_SEQSHIFT; 144 145 err = fuse_vnode_size(vp, &filesize, cred, curthread); 146 if (err) 147 return err; 148 149 for (err = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { 150 if (fuse_isdeadfs(vp)) { 151 err = ENXIO; 152 break; 153 } 154 if (filesize - uio->uio_offset <= 0) 155 break; 156 lbn = uio->uio_offset / biosize; 157 on = uio->uio_offset & (biosize - 1); 158 159 if ((off_t)lbn * biosize >= filesize) { 160 bcount = 0; 161 } else if ((off_t)(lbn + 1) * biosize > filesize) { 162 bcount = filesize - (off_t)lbn *biosize; 163 } else { 164 bcount = biosize; 165 } 166 nextlbn = lbn + 1; 167 nextsize = MIN(biosize, filesize - nextlbn * biosize); 168 169 SDT_PROBE4(fusefs, , io, read_bio_backend_start, 170 biosize, (int)lbn, on, bcount); 171 172 if (bcount < biosize) { 173 /* If near EOF, don't do readahead */ 174 err = bread(vp, lbn, bcount, NOCRED, &bp); 175 } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) { 176 /* Try clustered read */ 177 long totread = uio->uio_resid + on; 178 seqcount = MIN(seqcount, 179 data->max_readahead_blocks + 1); 180 err = cluster_read(vp, filesize, lbn, bcount, NOCRED, 181 totread, seqcount, 0, &bp); 182 } else if (seqcount > 1 && data->max_readahead_blocks >= 1) { 183 /* Try non-clustered readahead */ 184 err = breadn(vp, lbn, bcount, &nextlbn, &nextsize, 1, 185 NOCRED, &bp); 186 } else { 187 /* Just read what was requested */ 188 err = bread(vp, lbn, bcount, NOCRED, &bp); 189 } 190 191 if (err) { 192 brelse(bp); 193 bp = NULL; 194 break; 195 } 196 197 /* 198 * on is the offset into the current bp. Figure out how many 199 * bytes we can copy out of the bp. Note that bcount is 200 * NOT DEV_BSIZE aligned. 201 * 202 * Then figure out how many bytes we can copy into the uio. 203 */ 204 205 n = 0; 206 if (on < bcount - bp->b_resid) 207 n = MIN((unsigned)(bcount - bp->b_resid - on), 208 uio->uio_resid); 209 if (n > 0) { 210 SDT_PROBE2(fusefs, , io, read_bio_backend_feed, n, bp); 211 err = uiomove(bp->b_data + on, n, uio); 212 } 213 vfs_bio_brelse(bp, ioflag); 214 SDT_PROBE4(fusefs, , io, read_bio_backend_end, err, 215 uio->uio_resid, n, bp); 216 if (bp->b_resid > 0) { 217 /* Short read indicates EOF */ 218 break; 219 } 220 } 221 222 return (err); 223 } 224 225 SDT_PROBE_DEFINE1(fusefs, , io, read_directbackend_start, 226 "struct fuse_read_in*"); 227 SDT_PROBE_DEFINE3(fusefs, , io, read_directbackend_complete, 228 "struct fuse_dispatcher*", "struct fuse_read_in*", "struct uio*"); 229 230 int 231 fuse_read_directbackend(struct vnode *vp, struct uio *uio, 232 struct ucred *cred, struct fuse_filehandle *fufh) 233 { 234 struct fuse_data *data; 235 struct fuse_dispatcher fdi; 236 struct fuse_read_in *fri; 237 int err = 0; 238 239 data = fuse_get_mpdata(vp->v_mount); 240 241 if (uio->uio_resid == 0) 242 return (0); 243 244 fdisp_init(&fdi, 0); 245 246 /* 247 * XXX In "normal" case we use an intermediate kernel buffer for 248 * transmitting data from daemon's context to ours. Eventually, we should 249 * get rid of this. Anyway, if the target uio lives in sysspace (we are 250 * called from pageops), and the input data doesn't need kernel-side 251 * processing (we are not called from readdir) we can already invoke 252 * an optimized, "peer-to-peer" I/O routine. 253 */ 254 while (uio->uio_resid > 0) { 255 fdi.iosize = sizeof(*fri); 256 fdisp_make_vp(&fdi, FUSE_READ, vp, uio->uio_td, cred); 257 fri = fdi.indata; 258 fri->fh = fufh->fh_id; 259 fri->offset = uio->uio_offset; 260 fri->size = MIN(uio->uio_resid, 261 fuse_get_mpdata(vp->v_mount)->max_read); 262 if (fuse_libabi_geq(data, 7, 9)) { 263 /* See comment regarding FUSE_WRITE_LOCKOWNER */ 264 fri->read_flags = 0; 265 fri->flags = fufh_type_2_fflags(fufh->fufh_type); 266 } 267 268 SDT_PROBE1(fusefs, , io, read_directbackend_start, fri); 269 270 if ((err = fdisp_wait_answ(&fdi))) 271 goto out; 272 273 SDT_PROBE3(fusefs, , io, read_directbackend_complete, 274 &fdi, fri, uio); 275 276 if ((err = uiomove(fdi.answ, MIN(fri->size, fdi.iosize), uio))) 277 break; 278 if (fdi.iosize < fri->size) { 279 /* 280 * Short read. Should only happen at EOF or with 281 * direct io. 282 */ 283 break; 284 } 285 } 286 287 out: 288 fdisp_destroy(&fdi); 289 return (err); 290 } 291 292 int 293 fuse_write_directbackend(struct vnode *vp, struct uio *uio, 294 struct ucred *cred, struct fuse_filehandle *fufh, off_t filesize, 295 int ioflag, bool pages) 296 { 297 struct fuse_vnode_data *fvdat = VTOFUD(vp); 298 struct fuse_data *data; 299 struct fuse_write_in *fwi; 300 struct fuse_write_out *fwo; 301 struct fuse_dispatcher fdi; 302 size_t chunksize; 303 ssize_t r; 304 void *fwi_data; 305 off_t as_written_offset; 306 int diff; 307 int err = 0; 308 bool direct_io = fufh->fuse_open_flags & FOPEN_DIRECT_IO; 309 bool wrote_anything = false; 310 uint32_t write_flags; 311 312 data = fuse_get_mpdata(vp->v_mount); 313 314 /* 315 * Don't set FUSE_WRITE_LOCKOWNER in write_flags. It can't be set 316 * accurately when using POSIX AIO, libfuse doesn't use it, and I'm not 317 * aware of any file systems that do. It was an attempt to add 318 * Linux-style mandatory locking to the FUSE protocol, but mandatory 319 * locking is deprecated even on Linux. See Linux commit 320 * f33321141b273d60cbb3a8f56a5489baad82ba5e . 321 */ 322 /* 323 * Set FUSE_WRITE_CACHE whenever we don't know the uid, gid, and/or pid 324 * that originated a write. For example when writing from the 325 * writeback cache. I don't know of a single file system that cares, 326 * but the protocol says we're supposed to do this. 327 */ 328 write_flags = !pages && ( 329 (ioflag & IO_DIRECT) || 330 !fsess_opt_datacache(vnode_mount(vp)) || 331 !fsess_opt_writeback(vnode_mount(vp))) ? 0 : FUSE_WRITE_CACHE; 332 333 if (uio->uio_resid == 0) 334 return (0); 335 336 if (ioflag & IO_APPEND) 337 uio_setoffset(uio, filesize); 338 339 err = vn_rlimit_fsizex(vp, uio, 0, &r, uio->uio_td); 340 if (err != 0) { 341 vn_rlimit_fsizex_res(uio, r); 342 return (err); 343 } 344 345 fdisp_init(&fdi, 0); 346 347 while (uio->uio_resid > 0) { 348 size_t sizeof_fwi; 349 350 if (fuse_libabi_geq(data, 7, 9)) { 351 sizeof_fwi = sizeof(*fwi); 352 } else { 353 sizeof_fwi = FUSE_COMPAT_WRITE_IN_SIZE; 354 } 355 356 chunksize = MIN(uio->uio_resid, data->max_write); 357 358 fdi.iosize = sizeof_fwi + chunksize; 359 fdisp_make_vp(&fdi, FUSE_WRITE, vp, uio->uio_td, cred); 360 361 fwi = fdi.indata; 362 fwi->fh = fufh->fh_id; 363 fwi->offset = uio->uio_offset; 364 fwi->size = chunksize; 365 fwi->write_flags = write_flags; 366 if (fuse_libabi_geq(data, 7, 9)) { 367 fwi->flags = fufh_type_2_fflags(fufh->fufh_type); 368 } 369 fwi_data = (char *)fdi.indata + sizeof_fwi; 370 371 if ((err = uiomove(fwi_data, chunksize, uio))) 372 break; 373 374 retry: 375 err = fdisp_wait_answ(&fdi); 376 if (err == ERESTART || err == EINTR || err == EWOULDBLOCK) { 377 /* 378 * Rewind the uio so dofilewrite will know it's 379 * incomplete 380 */ 381 uio->uio_resid += fwi->size; 382 uio->uio_offset -= fwi->size; 383 /* 384 * Change ERESTART into EINTR because we can't rewind 385 * uio->uio_iov. Basically, once uiomove(9) has been 386 * called, it's impossible to restart a syscall. 387 */ 388 if (err == ERESTART) 389 err = EINTR; 390 break; 391 } else if (err) { 392 break; 393 } else { 394 wrote_anything = true; 395 } 396 397 fwo = ((struct fuse_write_out *)fdi.answ); 398 399 if (fwo->size > fwi->size) { 400 fuse_warn(data, FSESS_WARN_WROTE_LONG, 401 "wrote more data than we provided it."); 402 /* This is bonkers. Clear attr cache. */ 403 fvdat->flag &= ~FN_SIZECHANGE; 404 fuse_vnode_clear_attr_cache(vp); 405 err = EINVAL; 406 break; 407 } 408 409 /* Adjust the uio in the case of short writes */ 410 diff = fwi->size - fwo->size; 411 412 as_written_offset = uio->uio_offset - diff; 413 414 if (as_written_offset - diff > filesize) { 415 fuse_vnode_setsize(vp, as_written_offset, false); 416 getnanouptime(&fvdat->last_local_modify); 417 } 418 if (as_written_offset - diff >= filesize) 419 fvdat->flag &= ~FN_SIZECHANGE; 420 421 if (diff > 0) { 422 /* Short write */ 423 if (!direct_io) { 424 fuse_warn(data, FSESS_WARN_SHORT_WRITE, 425 "short writes are only allowed with " 426 "direct_io."); 427 } 428 if (ioflag & IO_DIRECT) { 429 /* Return early */ 430 uio->uio_resid += diff; 431 uio->uio_offset -= diff; 432 break; 433 } else { 434 /* Resend the unwritten portion of data */ 435 fdi.iosize = sizeof_fwi + diff; 436 /* Refresh fdi without clearing data buffer */ 437 fdisp_refresh_vp(&fdi, FUSE_WRITE, vp, 438 uio->uio_td, cred); 439 fwi = fdi.indata; 440 MPASS2(fwi == fdi.indata, "FUSE dispatcher " 441 "reallocated despite no increase in " 442 "size?"); 443 void *src = (char*)fwi_data + fwo->size; 444 memmove(fwi_data, src, diff); 445 fwi->fh = fufh->fh_id; 446 fwi->offset = as_written_offset; 447 fwi->size = diff; 448 fwi->write_flags = write_flags; 449 goto retry; 450 } 451 } 452 } 453 454 fdisp_destroy(&fdi); 455 456 if (wrote_anything) 457 fuse_vnode_undirty_cached_timestamps(vp, false); 458 459 vn_rlimit_fsizex_res(uio, r); 460 return (err); 461 } 462 463 SDT_PROBE_DEFINE6(fusefs, , io, write_biobackend_start, "int64_t", "int", "int", 464 "struct uio*", "int", "bool"); 465 SDT_PROBE_DEFINE2(fusefs, , io, write_biobackend_append_race, "long", "int"); 466 SDT_PROBE_DEFINE2(fusefs, , io, write_biobackend_issue, "int", "struct buf*"); 467 468 int 469 fuse_write_biobackend(struct vnode *vp, struct uio *uio, 470 struct ucred *cred, struct fuse_filehandle *fufh, int ioflag, pid_t pid) 471 { 472 struct fuse_vnode_data *fvdat = VTOFUD(vp); 473 struct buf *bp; 474 daddr_t lbn; 475 off_t filesize; 476 ssize_t r; 477 int bcount; 478 int n, on, seqcount, err = 0; 479 480 const int biosize = fuse_iosize(vp); 481 482 seqcount = ioflag >> IO_SEQSHIFT; 483 484 KASSERT(uio->uio_rw == UIO_WRITE, ("fuse_write_biobackend mode")); 485 if (vp->v_type != VREG) 486 return (EIO); 487 if (uio->uio_offset < 0) 488 return (EINVAL); 489 if (uio->uio_resid == 0) 490 return (0); 491 492 err = fuse_vnode_size(vp, &filesize, cred, curthread); 493 if (err) 494 return err; 495 496 if (ioflag & IO_APPEND) 497 uio_setoffset(uio, filesize); 498 499 err = vn_rlimit_fsizex(vp, uio, 0, &r, uio->uio_td); 500 if (err != 0) { 501 vn_rlimit_fsizex_res(uio, r); 502 return (err); 503 } 504 505 do { 506 bool direct_append, extending; 507 508 if (fuse_isdeadfs(vp)) { 509 err = ENXIO; 510 break; 511 } 512 lbn = uio->uio_offset / biosize; 513 on = uio->uio_offset & (biosize - 1); 514 n = MIN((unsigned)(biosize - on), uio->uio_resid); 515 516 again: 517 /* Get or create a buffer for the write */ 518 direct_append = uio->uio_offset == filesize && n; 519 if (uio->uio_offset + n < filesize) { 520 extending = false; 521 if ((off_t)(lbn + 1) * biosize < filesize) { 522 /* Not the file's last block */ 523 bcount = biosize; 524 } else { 525 /* The file's last block */ 526 bcount = filesize - (off_t)lbn * biosize; 527 } 528 } else { 529 extending = true; 530 bcount = on + n; 531 } 532 if (direct_append) { 533 /* 534 * Take care to preserve the buffer's B_CACHE state so 535 * as not to cause an unnecessary read. 536 */ 537 bp = getblk(vp, lbn, on, PCATCH, 0, 0); 538 if (bp != NULL) { 539 uint32_t save = bp->b_flags & B_CACHE; 540 allocbuf(bp, bcount); 541 bp->b_flags |= save; 542 } 543 } else { 544 bp = getblk(vp, lbn, bcount, PCATCH, 0, 0); 545 } 546 if (!bp) { 547 err = EINTR; 548 break; 549 } 550 if (extending) { 551 /* 552 * Extend file _after_ locking buffer so we won't race 553 * with other readers 554 */ 555 err = fuse_vnode_setsize(vp, uio->uio_offset + n, false); 556 filesize = uio->uio_offset + n; 557 getnanouptime(&fvdat->last_local_modify); 558 fvdat->flag |= FN_SIZECHANGE; 559 if (err) { 560 brelse(bp); 561 break; 562 } 563 } 564 565 SDT_PROBE6(fusefs, , io, write_biobackend_start, 566 lbn, on, n, uio, bcount, direct_append); 567 /* 568 * Issue a READ if B_CACHE is not set. In special-append 569 * mode, B_CACHE is based on the buffer prior to the write 570 * op and is typically set, avoiding the read. If a read 571 * is required in special append mode, the server will 572 * probably send us a short-read since we extended the file 573 * on our end, resulting in b_resid == 0 and, thusly, 574 * B_CACHE getting set. 575 * 576 * We can also avoid issuing the read if the write covers 577 * the entire buffer. We have to make sure the buffer state 578 * is reasonable in this case since we will not be initiating 579 * I/O. See the comments in kern/vfs_bio.c's getblk() for 580 * more information. 581 * 582 * B_CACHE may also be set due to the buffer being cached 583 * normally. 584 */ 585 586 if (on == 0 && n == bcount) { 587 bp->b_flags |= B_CACHE; 588 bp->b_flags &= ~B_INVAL; 589 bp->b_ioflags &= ~BIO_ERROR; 590 } 591 if ((bp->b_flags & B_CACHE) == 0) { 592 bp->b_iocmd = BIO_READ; 593 vfs_busy_pages(bp, 0); 594 fuse_io_strategy(vp, bp); 595 if ((err = bp->b_error)) { 596 brelse(bp); 597 break; 598 } 599 if (bp->b_resid > 0) { 600 /* 601 * Short read indicates EOF. Update file size 602 * from the server and try again. 603 */ 604 SDT_PROBE2(fusefs, , io, trace, 1, 605 "Short read during a RMW"); 606 brelse(bp); 607 err = fuse_vnode_size(vp, &filesize, cred, 608 curthread); 609 if (err) 610 break; 611 else 612 goto again; 613 } 614 } 615 if (bp->b_wcred == NOCRED) 616 bp->b_wcred = crhold(cred); 617 618 /* 619 * If dirtyend exceeds file size, chop it down. This should 620 * not normally occur but there is an append race where it 621 * might occur XXX, so we log it. 622 * 623 * If the chopping creates a reverse-indexed or degenerate 624 * situation with dirtyoff/end, we 0 both of them. 625 */ 626 if (bp->b_dirtyend > bcount) { 627 SDT_PROBE2(fusefs, , io, write_biobackend_append_race, 628 (long)bp->b_blkno * biosize, 629 bp->b_dirtyend - bcount); 630 bp->b_dirtyend = bcount; 631 } 632 if (bp->b_dirtyoff >= bp->b_dirtyend) 633 bp->b_dirtyoff = bp->b_dirtyend = 0; 634 635 /* 636 * If the new write will leave a contiguous dirty 637 * area, just update the b_dirtyoff and b_dirtyend, 638 * otherwise force a write rpc of the old dirty area. 639 * 640 * While it is possible to merge discontiguous writes due to 641 * our having a B_CACHE buffer ( and thus valid read data 642 * for the hole), we don't because it could lead to 643 * significant cache coherency problems with multiple clients, 644 * especially if locking is implemented later on. 645 * 646 * as an optimization we could theoretically maintain 647 * a linked list of discontinuous areas, but we would still 648 * have to commit them separately so there isn't much 649 * advantage to it except perhaps a bit of asynchronization. 650 */ 651 652 if (bp->b_dirtyend > 0 && 653 (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) { 654 /* 655 * Yes, we mean it. Write out everything to "storage" 656 * immediately, without hesitation. (Apart from other 657 * reasons: the only way to know if a write is valid 658 * if its actually written out.) 659 */ 660 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 0, bp); 661 bwrite(bp); 662 if (bp->b_error == EINTR) { 663 err = EINTR; 664 break; 665 } 666 goto again; 667 } 668 err = uiomove((char *)bp->b_data + on, n, uio); 669 670 if (err) { 671 bp->b_ioflags |= BIO_ERROR; 672 bp->b_error = err; 673 brelse(bp); 674 break; 675 /* TODO: vfs_bio_clrbuf like ffs_write does? */ 676 } 677 /* 678 * Only update dirtyoff/dirtyend if not a degenerate 679 * condition. 680 */ 681 if (n) { 682 if (bp->b_dirtyend > 0) { 683 bp->b_dirtyoff = MIN(on, bp->b_dirtyoff); 684 bp->b_dirtyend = MAX((on + n), bp->b_dirtyend); 685 } else { 686 bp->b_dirtyoff = on; 687 bp->b_dirtyend = on + n; 688 } 689 vfs_bio_set_valid(bp, on, n); 690 } 691 692 vfs_bio_set_flags(bp, ioflag); 693 694 bp->b_flags |= B_FUSEFS_WRITE_CACHE; 695 if (ioflag & IO_SYNC) { 696 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 2, bp); 697 if (!(ioflag & IO_VMIO)) 698 bp->b_flags &= ~B_FUSEFS_WRITE_CACHE; 699 err = bwrite(bp); 700 } else if (vm_page_count_severe() || 701 buf_dirty_count_severe() || 702 (ioflag & IO_ASYNC)) { 703 bp->b_flags |= B_CLUSTEROK; 704 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 3, bp); 705 bawrite(bp); 706 } else if (on == 0 && n == bcount) { 707 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) { 708 bp->b_flags |= B_CLUSTEROK; 709 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 710 4, bp); 711 cluster_write(vp, &fvdat->clusterw, bp, 712 filesize, seqcount, 0); 713 } else { 714 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 715 5, bp); 716 bawrite(bp); 717 } 718 } else if (ioflag & IO_DIRECT) { 719 bp->b_flags |= B_CLUSTEROK; 720 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 6, bp); 721 bawrite(bp); 722 } else { 723 bp->b_flags &= ~B_CLUSTEROK; 724 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 7, bp); 725 bdwrite(bp); 726 } 727 if (err) 728 break; 729 } while (uio->uio_resid > 0 && n > 0); 730 731 vn_rlimit_fsizex_res(uio, r); 732 return (err); 733 } 734 735 int 736 fuse_io_strategy(struct vnode *vp, struct buf *bp) 737 { 738 struct fuse_vnode_data *fvdat = VTOFUD(vp); 739 struct fuse_filehandle *fufh; 740 struct ucred *cred; 741 struct uio *uiop; 742 struct uio uio; 743 struct iovec io; 744 off_t filesize; 745 int error = 0; 746 int fflag; 747 /* We don't know the true pid when we're dealing with the cache */ 748 pid_t pid = 0; 749 750 const int biosize = fuse_iosize(vp); 751 752 MPASS(vp->v_type == VREG || vp->v_type == VDIR); 753 MPASS(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE); 754 755 fflag = bp->b_iocmd == BIO_READ ? FREAD : FWRITE; 756 cred = bp->b_iocmd == BIO_READ ? bp->b_rcred : bp->b_wcred; 757 error = fuse_filehandle_getrw(vp, fflag, &fufh, cred, pid); 758 if (bp->b_iocmd == BIO_READ && error == EBADF) { 759 /* 760 * This may be a read-modify-write operation on a cached file 761 * opened O_WRONLY. The FUSE protocol allows this. 762 */ 763 error = fuse_filehandle_get(vp, FWRITE, &fufh, cred, pid); 764 } 765 if (error) { 766 printf("FUSE: strategy: filehandles are closed\n"); 767 bp->b_ioflags |= BIO_ERROR; 768 bp->b_error = error; 769 bufdone(bp); 770 return (error); 771 } 772 773 uiop = &uio; 774 uiop->uio_iov = &io; 775 uiop->uio_iovcnt = 1; 776 uiop->uio_segflg = UIO_SYSSPACE; 777 uiop->uio_td = curthread; 778 779 /* 780 * clear BIO_ERROR and B_INVAL state prior to initiating the I/O. We 781 * do this here so we do not have to do it in all the code that 782 * calls us. 783 */ 784 bp->b_flags &= ~B_INVAL; 785 bp->b_ioflags &= ~BIO_ERROR; 786 787 KASSERT(!(bp->b_flags & B_DONE), 788 ("fuse_io_strategy: bp %p already marked done", bp)); 789 if (bp->b_iocmd == BIO_READ) { 790 ssize_t left; 791 792 io.iov_len = uiop->uio_resid = bp->b_bcount; 793 io.iov_base = bp->b_data; 794 uiop->uio_rw = UIO_READ; 795 796 uiop->uio_offset = ((off_t)bp->b_lblkno) * biosize; 797 error = fuse_read_directbackend(vp, uiop, cred, fufh); 798 /* 799 * Store the amount we failed to read in the buffer's private 800 * field, so callers can truncate the file if necessary' 801 */ 802 803 if (!error && uiop->uio_resid) { 804 int nread = bp->b_bcount - uiop->uio_resid; 805 left = uiop->uio_resid; 806 bzero((char *)bp->b_data + nread, left); 807 808 if ((fvdat->flag & FN_SIZECHANGE) == 0) { 809 /* 810 * A short read with no error, when not using 811 * direct io, and when no writes are cached, 812 * indicates EOF caused by a server-side 813 * truncation. Clear the attr cache so we'll 814 * pick up the new file size and timestamps. 815 * 816 * We must still bzero the remaining buffer so 817 * uninitialized data doesn't get exposed by a 818 * future truncate that extends the file. 819 * 820 * To prevent lock order problems, we must 821 * truncate the file upstack, not here. 822 */ 823 SDT_PROBE2(fusefs, , io, trace, 1, 824 "Short read of a clean file"); 825 fuse_vnode_clear_attr_cache(vp); 826 } else { 827 /* 828 * If dirty writes _are_ cached beyond EOF, 829 * that indicates a newly created hole that the 830 * server doesn't know about. Those don't pose 831 * any problem. 832 * XXX: we don't currently track whether dirty 833 * writes are cached beyond EOF, before EOF, or 834 * both. 835 */ 836 SDT_PROBE2(fusefs, , io, trace, 1, 837 "Short read of a dirty file"); 838 uiop->uio_resid = 0; 839 } 840 } 841 if (error) { 842 bp->b_ioflags |= BIO_ERROR; 843 bp->b_error = error; 844 } 845 } else { 846 /* 847 * Setup for actual write 848 */ 849 /* 850 * If the file's size is cached, use that value, even if the 851 * cache is expired. At this point we're already committed to 852 * writing something. If the FUSE server has changed the 853 * file's size behind our back, it's too late for us to do 854 * anything about it. In particular, we can't invalidate any 855 * part of the file's buffers because VOP_STRATEGY is called 856 * with them already locked. 857 */ 858 filesize = fvdat->cached_attrs.va_size; 859 /* filesize must've been cached by fuse_vnop_open. */ 860 KASSERT(filesize != VNOVAL, ("filesize should've been cached")); 861 862 if ((off_t)bp->b_lblkno * biosize + bp->b_dirtyend > filesize) 863 bp->b_dirtyend = filesize - 864 (off_t)bp->b_lblkno * biosize; 865 866 if (bp->b_dirtyend > bp->b_dirtyoff) { 867 io.iov_len = uiop->uio_resid = bp->b_dirtyend 868 - bp->b_dirtyoff; 869 uiop->uio_offset = (off_t)bp->b_lblkno * biosize 870 + bp->b_dirtyoff; 871 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff; 872 uiop->uio_rw = UIO_WRITE; 873 874 bool pages = bp->b_flags & B_FUSEFS_WRITE_CACHE; 875 error = fuse_write_directbackend(vp, uiop, cred, fufh, 876 filesize, 0, pages); 877 878 if (error == EINTR || error == ETIMEDOUT) { 879 bp->b_flags &= ~(B_INVAL | B_NOCACHE); 880 if ((bp->b_flags & B_PAGING) == 0) { 881 bdirty(bp); 882 bp->b_flags &= ~B_DONE; 883 } 884 if ((error == EINTR || error == ETIMEDOUT) && 885 (bp->b_flags & B_ASYNC) == 0) 886 bp->b_flags |= B_EINTR; 887 } else { 888 if (error) { 889 bp->b_ioflags |= BIO_ERROR; 890 bp->b_flags |= B_INVAL; 891 bp->b_error = error; 892 } 893 bp->b_dirtyoff = bp->b_dirtyend = 0; 894 } 895 } else { 896 bp->b_resid = 0; 897 bufdone(bp); 898 return (0); 899 } 900 } 901 bp->b_resid = uiop->uio_resid; 902 bufdone(bp); 903 return (error); 904 } 905 906 int 907 fuse_io_flushbuf(struct vnode *vp, int waitfor, struct thread *td) 908 { 909 910 return (vn_fsync_buf(vp, waitfor)); 911 } 912 913 /* 914 * Flush and invalidate all dirty buffers. If another process is already 915 * doing the flush, just wait for completion. 916 */ 917 int 918 fuse_io_invalbuf(struct vnode *vp, struct thread *td) 919 { 920 struct fuse_vnode_data *fvdat = VTOFUD(vp); 921 int error = 0; 922 923 if (VN_IS_DOOMED(vp)) 924 return 0; 925 926 ASSERT_VOP_ELOCKED(vp, "fuse_io_invalbuf"); 927 928 while (fvdat->flag & FN_FLUSHINPROG) { 929 struct proc *p = td->td_proc; 930 931 if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) 932 return EIO; 933 fvdat->flag |= FN_FLUSHWANT; 934 tsleep(&fvdat->flag, PRIBIO + 2, "fusevinv", 2 * hz); 935 error = 0; 936 if (p != NULL) { 937 PROC_LOCK(p); 938 if (SIGNOTEMPTY(p->p_siglist) || 939 SIGNOTEMPTY(td->td_siglist)) 940 error = EINTR; 941 PROC_UNLOCK(p); 942 } 943 if (error == EINTR) 944 return EINTR; 945 } 946 fvdat->flag |= FN_FLUSHINPROG; 947 948 if (vp->v_bufobj.bo_object != NULL) { 949 VM_OBJECT_WLOCK(vp->v_bufobj.bo_object); 950 vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC); 951 VM_OBJECT_WUNLOCK(vp->v_bufobj.bo_object); 952 } 953 error = vinvalbuf(vp, V_SAVE, PCATCH, 0); 954 while (error) { 955 if (error == ERESTART || error == EINTR) { 956 fvdat->flag &= ~FN_FLUSHINPROG; 957 if (fvdat->flag & FN_FLUSHWANT) { 958 fvdat->flag &= ~FN_FLUSHWANT; 959 wakeup(&fvdat->flag); 960 } 961 return EINTR; 962 } 963 error = vinvalbuf(vp, V_SAVE, PCATCH, 0); 964 } 965 fvdat->flag &= ~FN_FLUSHINPROG; 966 if (fvdat->flag & FN_FLUSHWANT) { 967 fvdat->flag &= ~FN_FLUSHWANT; 968 wakeup(&fvdat->flag); 969 } 970 return (error); 971 } 972