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