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 ASSERT_CACHED_ATTRS_LOCKED(vp); 405 fvdat->flag &= ~FN_SIZECHANGE; 406 fuse_vnode_clear_attr_cache(vp); 407 err = EINVAL; 408 break; 409 } 410 411 /* Adjust the uio in the case of short writes */ 412 diff = fwi->size - fwo->size; 413 414 as_written_offset = uio->uio_offset - diff; 415 416 if (as_written_offset - diff > filesize) { 417 fuse_vnode_setsize(vp, as_written_offset, false); 418 getnanouptime(&fvdat->last_local_modify); 419 } 420 if (as_written_offset - diff >= filesize) { 421 ASSERT_CACHED_ATTRS_LOCKED(vp); 422 fvdat->flag &= ~FN_SIZECHANGE; 423 } 424 425 if (diff > 0) { 426 /* Short write */ 427 if (!direct_io) { 428 fuse_warn(data, FSESS_WARN_SHORT_WRITE, 429 "short writes are only allowed with " 430 "direct_io."); 431 } 432 if (ioflag & IO_DIRECT) { 433 /* Return early */ 434 uio->uio_resid += diff; 435 uio->uio_offset -= diff; 436 break; 437 } else { 438 /* Resend the unwritten portion of data */ 439 fdi.iosize = sizeof_fwi + diff; 440 /* Refresh fdi without clearing data buffer */ 441 fdisp_refresh_vp(&fdi, FUSE_WRITE, vp, 442 uio->uio_td, cred); 443 fwi = fdi.indata; 444 MPASS2(fwi == fdi.indata, "FUSE dispatcher " 445 "reallocated despite no increase in " 446 "size?"); 447 void *src = (char*)fwi_data + fwo->size; 448 memmove(fwi_data, src, diff); 449 fwi->fh = fufh->fh_id; 450 fwi->offset = as_written_offset; 451 fwi->size = diff; 452 fwi->write_flags = write_flags; 453 goto retry; 454 } 455 } 456 } 457 458 fdisp_destroy(&fdi); 459 460 if (wrote_anything) { 461 CACHED_ATTR_LOCK(vp); 462 fuse_vnode_undirty_cached_timestamps(vp, false); 463 CACHED_ATTR_UNLOCK(vp); 464 } 465 466 vn_rlimit_fsizex_res(uio, r); 467 return (err); 468 } 469 470 SDT_PROBE_DEFINE6(fusefs, , io, write_biobackend_start, "int64_t", "int", "int", 471 "struct uio*", "int", "bool"); 472 SDT_PROBE_DEFINE2(fusefs, , io, write_biobackend_append_race, "long", "int"); 473 SDT_PROBE_DEFINE2(fusefs, , io, write_biobackend_issue, "int", "struct buf*"); 474 475 int 476 fuse_write_biobackend(struct vnode *vp, struct uio *uio, 477 struct ucred *cred, struct fuse_filehandle *fufh, int ioflag, pid_t pid) 478 { 479 struct fuse_vnode_data *fvdat = VTOFUD(vp); 480 struct buf *bp; 481 daddr_t lbn; 482 off_t filesize; 483 ssize_t r; 484 int bcount; 485 int n, on, seqcount, err = 0; 486 487 const int biosize = fuse_iosize(vp); 488 489 seqcount = ioflag >> IO_SEQSHIFT; 490 491 KASSERT(uio->uio_rw == UIO_WRITE, ("fuse_write_biobackend mode")); 492 if (vp->v_type != VREG) 493 return (EIO); 494 if (uio->uio_offset < 0) 495 return (EINVAL); 496 if (uio->uio_resid == 0) 497 return (0); 498 499 err = fuse_vnode_size(vp, &filesize, cred, curthread); 500 if (err) 501 return err; 502 503 if (ioflag & IO_APPEND) 504 uio_setoffset(uio, filesize); 505 506 err = vn_rlimit_fsizex(vp, uio, 0, &r, uio->uio_td); 507 if (err != 0) { 508 vn_rlimit_fsizex_res(uio, r); 509 return (err); 510 } 511 512 do { 513 bool direct_append, extending; 514 515 if (fuse_isdeadfs(vp)) { 516 err = ENXIO; 517 break; 518 } 519 lbn = uio->uio_offset / biosize; 520 on = uio->uio_offset & (biosize - 1); 521 n = MIN((unsigned)(biosize - on), uio->uio_resid); 522 523 again: 524 /* Get or create a buffer for the write */ 525 direct_append = uio->uio_offset == filesize && n; 526 if (uio->uio_offset + n < filesize) { 527 extending = false; 528 if ((off_t)(lbn + 1) * biosize < filesize) { 529 /* Not the file's last block */ 530 bcount = biosize; 531 } else { 532 /* The file's last block */ 533 bcount = filesize - (off_t)lbn * biosize; 534 } 535 } else { 536 extending = true; 537 bcount = on + n; 538 } 539 if (direct_append) { 540 /* 541 * Take care to preserve the buffer's B_CACHE state so 542 * as not to cause an unnecessary read. 543 */ 544 bp = getblk(vp, lbn, on, PCATCH, 0, 0); 545 if (bp != NULL) { 546 uint32_t save = bp->b_flags & B_CACHE; 547 allocbuf(bp, bcount); 548 bp->b_flags |= save; 549 } 550 } else { 551 bp = getblk(vp, lbn, bcount, PCATCH, 0, 0); 552 } 553 if (!bp) { 554 err = EINTR; 555 break; 556 } 557 if (extending) { 558 /* 559 * Extend file _after_ locking buffer so we won't race 560 * with other readers 561 */ 562 err = fuse_vnode_setsize(vp, uio->uio_offset + n, false); 563 filesize = uio->uio_offset + n; 564 getnanouptime(&fvdat->last_local_modify); 565 ASSERT_CACHED_ATTRS_LOCKED(vp); 566 fvdat->flag |= FN_SIZECHANGE; 567 if (err) { 568 brelse(bp); 569 break; 570 } 571 } 572 573 SDT_PROBE6(fusefs, , io, write_biobackend_start, 574 lbn, on, n, uio, bcount, direct_append); 575 /* 576 * Issue a READ if B_CACHE is not set. In special-append 577 * mode, B_CACHE is based on the buffer prior to the write 578 * op and is typically set, avoiding the read. If a read 579 * is required in special append mode, the server will 580 * probably send us a short-read since we extended the file 581 * on our end, resulting in b_resid == 0 and, thusly, 582 * B_CACHE getting set. 583 * 584 * We can also avoid issuing the read if the write covers 585 * the entire buffer. We have to make sure the buffer state 586 * is reasonable in this case since we will not be initiating 587 * I/O. See the comments in kern/vfs_bio.c's getblk() for 588 * more information. 589 * 590 * B_CACHE may also be set due to the buffer being cached 591 * normally. 592 */ 593 594 if (on == 0 && n == bcount) { 595 bp->b_flags |= B_CACHE; 596 bp->b_flags &= ~B_INVAL; 597 bp->b_ioflags &= ~BIO_ERROR; 598 } 599 if ((bp->b_flags & B_CACHE) == 0) { 600 bp->b_iocmd = BIO_READ; 601 vfs_busy_pages(bp, 0); 602 fuse_io_strategy(vp, bp); 603 if ((err = bp->b_error)) { 604 brelse(bp); 605 break; 606 } 607 if (bp->b_resid > 0) { 608 /* 609 * Short read indicates EOF. Update file size 610 * from the server and try again. 611 */ 612 SDT_PROBE2(fusefs, , io, trace, 1, 613 "Short read during a RMW"); 614 brelse(bp); 615 err = fuse_vnode_size(vp, &filesize, cred, 616 curthread); 617 if (err) 618 break; 619 else 620 goto again; 621 } 622 } 623 if (bp->b_wcred == NOCRED) 624 bp->b_wcred = crhold(cred); 625 626 /* 627 * If dirtyend exceeds file size, chop it down. This should 628 * not normally occur but there is an append race where it 629 * might occur XXX, so we log it. 630 * 631 * If the chopping creates a reverse-indexed or degenerate 632 * situation with dirtyoff/end, we 0 both of them. 633 */ 634 if (bp->b_dirtyend > bcount) { 635 SDT_PROBE2(fusefs, , io, write_biobackend_append_race, 636 (long)bp->b_blkno * biosize, 637 bp->b_dirtyend - bcount); 638 bp->b_dirtyend = bcount; 639 } 640 if (bp->b_dirtyoff >= bp->b_dirtyend) 641 bp->b_dirtyoff = bp->b_dirtyend = 0; 642 643 /* 644 * If the new write will leave a contiguous dirty 645 * area, just update the b_dirtyoff and b_dirtyend, 646 * otherwise force a write rpc of the old dirty area. 647 * 648 * While it is possible to merge discontiguous writes due to 649 * our having a B_CACHE buffer ( and thus valid read data 650 * for the hole), we don't because it could lead to 651 * significant cache coherency problems with multiple clients, 652 * especially if locking is implemented later on. 653 * 654 * as an optimization we could theoretically maintain 655 * a linked list of discontinuous areas, but we would still 656 * have to commit them separately so there isn't much 657 * advantage to it except perhaps a bit of asynchronization. 658 */ 659 660 if (bp->b_dirtyend > 0 && 661 (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) { 662 /* 663 * Yes, we mean it. Write out everything to "storage" 664 * immediately, without hesitation. (Apart from other 665 * reasons: the only way to know if a write is valid 666 * if its actually written out.) 667 */ 668 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 0, bp); 669 bwrite(bp); 670 if (bp->b_error == EINTR) { 671 err = EINTR; 672 break; 673 } 674 goto again; 675 } 676 err = uiomove((char *)bp->b_data + on, n, uio); 677 678 if (err) { 679 bp->b_ioflags |= BIO_ERROR; 680 bp->b_error = err; 681 brelse(bp); 682 break; 683 /* TODO: vfs_bio_clrbuf like ffs_write does? */ 684 } 685 /* 686 * Only update dirtyoff/dirtyend if not a degenerate 687 * condition. 688 */ 689 if (n) { 690 if (bp->b_dirtyend > 0) { 691 bp->b_dirtyoff = MIN(on, bp->b_dirtyoff); 692 bp->b_dirtyend = MAX((on + n), bp->b_dirtyend); 693 } else { 694 bp->b_dirtyoff = on; 695 bp->b_dirtyend = on + n; 696 } 697 vfs_bio_set_valid(bp, on, n); 698 } 699 700 vfs_bio_set_flags(bp, ioflag); 701 702 bp->b_flags |= B_FUSEFS_WRITE_CACHE; 703 if (ioflag & IO_SYNC) { 704 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 2, bp); 705 if (!(ioflag & IO_VMIO)) 706 bp->b_flags &= ~B_FUSEFS_WRITE_CACHE; 707 err = bwrite(bp); 708 } else if (vm_page_count_severe() || 709 buf_dirty_count_severe() || 710 (ioflag & IO_ASYNC)) { 711 bp->b_flags |= B_CLUSTEROK; 712 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 3, bp); 713 bawrite(bp); 714 } else if (on == 0 && n == bcount) { 715 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) { 716 bp->b_flags |= B_CLUSTEROK; 717 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 718 4, bp); 719 cluster_write(vp, &fvdat->clusterw, bp, 720 filesize, seqcount, 0); 721 } else { 722 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 723 5, bp); 724 bawrite(bp); 725 } 726 } else if (ioflag & IO_DIRECT) { 727 bp->b_flags |= B_CLUSTEROK; 728 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 6, bp); 729 bawrite(bp); 730 } else { 731 bp->b_flags &= ~B_CLUSTEROK; 732 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 7, bp); 733 bdwrite(bp); 734 } 735 if (err) 736 break; 737 } while (uio->uio_resid > 0 && n > 0); 738 739 vn_rlimit_fsizex_res(uio, r); 740 return (err); 741 } 742 743 int 744 fuse_io_strategy(struct vnode *vp, struct buf *bp) 745 { 746 struct fuse_vnode_data *fvdat = VTOFUD(vp); 747 struct fuse_filehandle *fufh; 748 struct ucred *cred; 749 struct uio *uiop; 750 struct uio uio; 751 struct iovec io; 752 off_t filesize; 753 int error = 0; 754 int fflag; 755 /* We don't know the true pid when we're dealing with the cache */ 756 pid_t pid = 0; 757 758 const int biosize = fuse_iosize(vp); 759 760 MPASS(vp->v_type == VREG || vp->v_type == VDIR); 761 MPASS(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE); 762 763 fflag = bp->b_iocmd == BIO_READ ? FREAD : FWRITE; 764 cred = bp->b_iocmd == BIO_READ ? bp->b_rcred : bp->b_wcred; 765 error = fuse_filehandle_getrw(vp, fflag, &fufh, cred, pid); 766 if (bp->b_iocmd == BIO_READ && error == EBADF) { 767 /* 768 * This may be a read-modify-write operation on a cached file 769 * opened O_WRONLY. The FUSE protocol allows this. 770 */ 771 error = fuse_filehandle_get(vp, FWRITE, &fufh, cred, pid); 772 } 773 if (error) { 774 printf("FUSE: strategy: filehandles are closed\n"); 775 bp->b_ioflags |= BIO_ERROR; 776 bp->b_error = error; 777 bufdone(bp); 778 return (error); 779 } 780 781 uiop = &uio; 782 uiop->uio_iov = &io; 783 uiop->uio_iovcnt = 1; 784 uiop->uio_segflg = UIO_SYSSPACE; 785 uiop->uio_td = curthread; 786 787 /* 788 * clear BIO_ERROR and B_INVAL state prior to initiating the I/O. We 789 * do this here so we do not have to do it in all the code that 790 * calls us. 791 */ 792 bp->b_flags &= ~B_INVAL; 793 bp->b_ioflags &= ~BIO_ERROR; 794 795 KASSERT(!(bp->b_flags & B_DONE), 796 ("fuse_io_strategy: bp %p already marked done", bp)); 797 if (bp->b_iocmd == BIO_READ) { 798 ssize_t left; 799 800 io.iov_len = uiop->uio_resid = bp->b_bcount; 801 io.iov_base = bp->b_data; 802 uiop->uio_rw = UIO_READ; 803 804 uiop->uio_offset = ((off_t)bp->b_lblkno) * biosize; 805 error = fuse_read_directbackend(vp, uiop, cred, fufh); 806 /* 807 * Store the amount we failed to read in the buffer's private 808 * field, so callers can truncate the file if necessary' 809 */ 810 811 if (!error && uiop->uio_resid) { 812 int nread = bp->b_bcount - uiop->uio_resid; 813 left = uiop->uio_resid; 814 bzero((char *)bp->b_data + nread, left); 815 816 CACHED_ATTR_LOCK(vp); 817 if ((fvdat->flag & FN_SIZECHANGE) == 0) { 818 /* 819 * A short read with no error, when not using 820 * direct io, and when no writes are cached, 821 * indicates EOF caused by a server-side 822 * truncation. Clear the attr cache so we'll 823 * pick up the new file size and timestamps. 824 * 825 * We must still bzero the remaining buffer so 826 * uninitialized data doesn't get exposed by a 827 * future truncate that extends the file. 828 * 829 * To prevent lock order problems, we must 830 * truncate the file upstack, not here. 831 */ 832 SDT_PROBE2(fusefs, , io, trace, 1, 833 "Short read of a clean file"); 834 fuse_vnode_clear_attr_cache(vp); 835 } else { 836 /* 837 * If dirty writes _are_ cached beyond EOF, 838 * that indicates a newly created hole that the 839 * server doesn't know about. Those don't pose 840 * any problem. 841 * XXX: we don't currently track whether dirty 842 * writes are cached beyond EOF, before EOF, or 843 * both. 844 */ 845 SDT_PROBE2(fusefs, , io, trace, 1, 846 "Short read of a dirty file"); 847 uiop->uio_resid = 0; 848 } 849 CACHED_ATTR_UNLOCK(vp); 850 } 851 if (error) { 852 bp->b_ioflags |= BIO_ERROR; 853 bp->b_error = error; 854 } 855 } else { 856 /* 857 * Setup for actual write 858 */ 859 /* 860 * If the file's size is cached, use that value, even if the 861 * cache is expired. At this point we're already committed to 862 * writing something. If the FUSE server has changed the 863 * file's size behind our back, it's too late for us to do 864 * anything about it. In particular, we can't invalidate any 865 * part of the file's buffers because VOP_STRATEGY is called 866 * with them already locked. 867 * 868 * Normally the vnode should be exclusively locked at this 869 * point. However, if clustered reads are in use, then in a 870 * mixed read-write workload getblkx may need to flush a 871 * partially written buffer to disk during a read. In such a 872 * case, the vnode may only have a shared lock at this point. 873 */ 874 CACHED_ATTR_LOCK(vp); 875 filesize = fvdat->cached_attrs.va_size; 876 /* filesize must've been cached by fuse_vnop_open. */ 877 KASSERT(filesize != VNOVAL, ("filesize should've been cached")); 878 CACHED_ATTR_UNLOCK(vp); 879 880 if ((off_t)bp->b_lblkno * biosize + bp->b_dirtyend > filesize) 881 bp->b_dirtyend = filesize - 882 (off_t)bp->b_lblkno * biosize; 883 884 if (bp->b_dirtyend > bp->b_dirtyoff) { 885 io.iov_len = uiop->uio_resid = bp->b_dirtyend 886 - bp->b_dirtyoff; 887 uiop->uio_offset = (off_t)bp->b_lblkno * biosize 888 + bp->b_dirtyoff; 889 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff; 890 uiop->uio_rw = UIO_WRITE; 891 892 bool pages = bp->b_flags & B_FUSEFS_WRITE_CACHE; 893 error = fuse_write_directbackend(vp, uiop, cred, fufh, 894 filesize, 0, pages); 895 896 if (error == EINTR || error == ETIMEDOUT) { 897 bp->b_flags &= ~(B_INVAL | B_NOCACHE); 898 if ((bp->b_flags & B_PAGING) == 0) { 899 bdirty(bp); 900 bp->b_flags &= ~B_DONE; 901 } 902 if ((error == EINTR || error == ETIMEDOUT) && 903 (bp->b_flags & B_ASYNC) == 0) 904 bp->b_flags |= B_EINTR; 905 } else { 906 if (error) { 907 bp->b_ioflags |= BIO_ERROR; 908 bp->b_flags |= B_INVAL; 909 bp->b_error = error; 910 } 911 bp->b_dirtyoff = bp->b_dirtyend = 0; 912 } 913 } else { 914 bp->b_resid = 0; 915 bufdone(bp); 916 return (0); 917 } 918 } 919 bp->b_resid = uiop->uio_resid; 920 bufdone(bp); 921 return (error); 922 } 923 924 int 925 fuse_io_flushbuf(struct vnode *vp, int waitfor, struct thread *td) 926 { 927 928 return (vn_fsync_buf(vp, waitfor)); 929 } 930 931 /* 932 * Flush and invalidate all dirty buffers. If another process is already 933 * doing the flush, just wait for completion. 934 */ 935 int 936 fuse_io_invalbuf(struct vnode *vp, struct thread *td) 937 { 938 struct fuse_vnode_data *fvdat = VTOFUD(vp); 939 int error = 0; 940 941 if (VN_IS_DOOMED(vp)) 942 return 0; 943 944 ASSERT_VOP_ELOCKED(vp, "fuse_io_invalbuf"); 945 946 while (fvdat->flag & FN_FLUSHINPROG) { 947 struct proc *p = td->td_proc; 948 949 if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) 950 return EIO; 951 fvdat->flag |= FN_FLUSHWANT; 952 tsleep(&fvdat->flag, PRIBIO, "fusevinv", 2 * hz); 953 error = 0; 954 if (p != NULL) { 955 PROC_LOCK(p); 956 if (SIGNOTEMPTY(p->p_siglist) || 957 SIGNOTEMPTY(td->td_siglist)) 958 error = EINTR; 959 PROC_UNLOCK(p); 960 } 961 if (error == EINTR) 962 return EINTR; 963 } 964 fvdat->flag |= FN_FLUSHINPROG; 965 966 vnode_pager_clean_sync(vp); 967 error = vinvalbuf(vp, V_SAVE, PCATCH, 0); 968 while (error) { 969 if (error == ERESTART || error == EINTR) { 970 fvdat->flag &= ~FN_FLUSHINPROG; 971 if (fvdat->flag & FN_FLUSHWANT) { 972 fvdat->flag &= ~FN_FLUSHWANT; 973 wakeup(&fvdat->flag); 974 } 975 return EINTR; 976 } 977 error = vinvalbuf(vp, V_SAVE, PCATCH, 0); 978 } 979 fvdat->flag &= ~FN_FLUSHINPROG; 980 if (fvdat->flag & FN_FLUSHWANT) { 981 fvdat->flag &= ~FN_FLUSHWANT; 982 wakeup(&fvdat->flag); 983 } 984 return (error); 985 } 986