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/cdefs.h> 64 __FBSDID("$FreeBSD$"); 65 66 #include <sys/types.h> 67 #include <sys/module.h> 68 #include <sys/systm.h> 69 #include <sys/errno.h> 70 #include <sys/param.h> 71 #include <sys/kernel.h> 72 #include <sys/conf.h> 73 #include <sys/uio.h> 74 #include <sys/malloc.h> 75 #include <sys/queue.h> 76 #include <sys/lock.h> 77 #include <sys/sx.h> 78 #include <sys/mutex.h> 79 #include <sys/rwlock.h> 80 #include <sys/priv.h> 81 #include <sys/proc.h> 82 #include <sys/mount.h> 83 #include <sys/vnode.h> 84 #include <sys/stat.h> 85 #include <sys/unistd.h> 86 #include <sys/filedesc.h> 87 #include <sys/file.h> 88 #include <sys/fcntl.h> 89 #include <sys/bio.h> 90 #include <sys/buf.h> 91 #include <sys/sysctl.h> 92 #include <sys/vmmeter.h> 93 94 #include <vm/vm.h> 95 #include <vm/vm_extern.h> 96 #include <vm/pmap.h> 97 #include <vm/vm_map.h> 98 #include <vm/vm_page.h> 99 #include <vm/vm_object.h> 100 101 #include "fuse.h" 102 #include "fuse_file.h" 103 #include "fuse_node.h" 104 #include "fuse_internal.h" 105 #include "fuse_ipc.h" 106 #include "fuse_io.h" 107 108 /* 109 * Set in a struct buf to indicate that the write came from the buffer cache 110 * and the originating cred and pid are no longer known. 111 */ 112 #define B_FUSEFS_WRITE_CACHE B_FS_FLAG1 113 114 SDT_PROVIDER_DECLARE(fusefs); 115 /* 116 * Fuse trace probe: 117 * arg0: verbosity. Higher numbers give more verbose messages 118 * arg1: Textual message 119 */ 120 SDT_PROBE_DEFINE2(fusefs, , io, trace, "int", "char*"); 121 122 static int 123 fuse_inval_buf_range(struct vnode *vp, off_t filesize, off_t start, off_t end); 124 static void 125 fuse_io_clear_suid_on_write(struct vnode *vp, struct ucred *cred, 126 struct thread *td); 127 static int 128 fuse_read_directbackend(struct vnode *vp, struct uio *uio, 129 struct ucred *cred, struct fuse_filehandle *fufh); 130 static int 131 fuse_read_biobackend(struct vnode *vp, struct uio *uio, int ioflag, 132 struct ucred *cred, struct fuse_filehandle *fufh, pid_t pid); 133 static int 134 fuse_write_directbackend(struct vnode *vp, struct uio *uio, 135 struct ucred *cred, struct fuse_filehandle *fufh, off_t filesize, 136 int ioflag, bool pages); 137 static int 138 fuse_write_biobackend(struct vnode *vp, struct uio *uio, 139 struct ucred *cred, struct fuse_filehandle *fufh, int ioflag, pid_t pid); 140 141 /* Invalidate a range of cached data, whether dirty of not */ 142 static int 143 fuse_inval_buf_range(struct vnode *vp, off_t filesize, off_t start, off_t end) 144 { 145 struct buf *bp; 146 daddr_t left_lbn, end_lbn, right_lbn; 147 off_t new_filesize; 148 int iosize, left_on, right_on, right_blksize; 149 150 iosize = fuse_iosize(vp); 151 left_lbn = start / iosize; 152 end_lbn = howmany(end, iosize); 153 left_on = start & (iosize - 1); 154 if (left_on != 0) { 155 bp = getblk(vp, left_lbn, iosize, PCATCH, 0, 0); 156 if ((bp->b_flags & B_CACHE) != 0 && bp->b_dirtyend >= left_on) { 157 /* 158 * Flush the dirty buffer, because we don't have a 159 * byte-granular way to record which parts of the 160 * buffer are valid. 161 */ 162 bwrite(bp); 163 if (bp->b_error) 164 return (bp->b_error); 165 } else { 166 brelse(bp); 167 } 168 } 169 right_on = end & (iosize - 1); 170 if (right_on != 0) { 171 right_lbn = end / iosize; 172 new_filesize = MAX(filesize, end); 173 right_blksize = MIN(iosize, new_filesize - iosize * right_lbn); 174 bp = getblk(vp, right_lbn, right_blksize, PCATCH, 0, 0); 175 if ((bp->b_flags & B_CACHE) != 0 && bp->b_dirtyoff < right_on) { 176 /* 177 * Flush the dirty buffer, because we don't have a 178 * byte-granular way to record which parts of the 179 * buffer are valid. 180 */ 181 bwrite(bp); 182 if (bp->b_error) 183 return (bp->b_error); 184 } else { 185 brelse(bp); 186 } 187 } 188 189 v_inval_buf_range(vp, left_lbn, end_lbn, iosize); 190 return (0); 191 } 192 193 /* 194 * FreeBSD clears the SUID and SGID bits on any write by a non-root user. 195 */ 196 static void 197 fuse_io_clear_suid_on_write(struct vnode *vp, struct ucred *cred, 198 struct thread *td) 199 { 200 struct fuse_data *data; 201 struct mount *mp; 202 struct vattr va; 203 int dataflags; 204 205 mp = vnode_mount(vp); 206 data = fuse_get_mpdata(mp); 207 dataflags = data->dataflags; 208 209 if (dataflags & FSESS_DEFAULT_PERMISSIONS) { 210 if (priv_check_cred(cred, PRIV_VFS_RETAINSUGID)) { 211 fuse_internal_getattr(vp, &va, cred, td); 212 if (va.va_mode & (S_ISUID | S_ISGID)) { 213 mode_t mode = va.va_mode & ~(S_ISUID | S_ISGID); 214 /* Clear all vattr fields except mode */ 215 vattr_null(&va); 216 va.va_mode = mode; 217 218 /* 219 * Ignore fuse_internal_setattr's return value, 220 * because at this point the write operation has 221 * already succeeded and we don't want to return 222 * failing status for that. 223 */ 224 (void)fuse_internal_setattr(vp, &va, td, NULL); 225 } 226 } 227 } 228 } 229 230 SDT_PROBE_DEFINE5(fusefs, , io, io_dispatch, "struct vnode*", "struct uio*", 231 "int", "struct ucred*", "struct fuse_filehandle*"); 232 SDT_PROBE_DEFINE4(fusefs, , io, io_dispatch_filehandles_closed, "struct vnode*", 233 "struct uio*", "int", "struct ucred*"); 234 int 235 fuse_io_dispatch(struct vnode *vp, struct uio *uio, int ioflag, 236 struct ucred *cred, pid_t pid) 237 { 238 struct fuse_filehandle *fufh; 239 int err, directio; 240 int fflag; 241 bool closefufh = false; 242 243 MPASS(vp->v_type == VREG || vp->v_type == VDIR); 244 245 fflag = (uio->uio_rw == UIO_READ) ? FREAD : FWRITE; 246 err = fuse_filehandle_getrw(vp, fflag, &fufh, cred, pid); 247 if (err == EBADF && vnode_mount(vp)->mnt_flag & MNT_EXPORTED) { 248 /* 249 * nfsd will do I/O without first doing VOP_OPEN. We 250 * must implicitly open the file here 251 */ 252 err = fuse_filehandle_open(vp, fflag, &fufh, curthread, cred); 253 closefufh = true; 254 } 255 else if (err) { 256 SDT_PROBE4(fusefs, , io, io_dispatch_filehandles_closed, 257 vp, uio, ioflag, cred); 258 printf("FUSE: io dispatch: filehandles are closed\n"); 259 return err; 260 } 261 if (err) 262 goto out; 263 SDT_PROBE5(fusefs, , io, io_dispatch, vp, uio, ioflag, cred, fufh); 264 265 /* 266 * Ideally, when the daemon asks for direct io at open time, the 267 * standard file flag should be set according to this, so that would 268 * just change the default mode, which later on could be changed via 269 * fcntl(2). 270 * But this doesn't work, the O_DIRECT flag gets cleared at some point 271 * (don't know where). So to make any use of the Fuse direct_io option, 272 * we hardwire it into the file's private data (similarly to Linux, 273 * btw.). 274 */ 275 directio = (ioflag & IO_DIRECT) || !fsess_opt_datacache(vnode_mount(vp)); 276 277 switch (uio->uio_rw) { 278 case UIO_READ: 279 if (directio) { 280 SDT_PROBE2(fusefs, , io, trace, 1, 281 "direct read of vnode"); 282 err = fuse_read_directbackend(vp, uio, cred, fufh); 283 } else { 284 SDT_PROBE2(fusefs, , io, trace, 1, 285 "buffered read of vnode"); 286 err = fuse_read_biobackend(vp, uio, ioflag, cred, fufh, 287 pid); 288 } 289 break; 290 case UIO_WRITE: 291 fuse_vnode_update(vp, FN_MTIMECHANGE | FN_CTIMECHANGE); 292 if (directio) { 293 off_t start, end, filesize; 294 295 SDT_PROBE2(fusefs, , io, trace, 1, 296 "direct write of vnode"); 297 298 err = fuse_vnode_size(vp, &filesize, cred, curthread); 299 if (err) 300 goto out; 301 302 start = uio->uio_offset; 303 end = start + uio->uio_resid; 304 KASSERT((ioflag & (IO_VMIO | IO_DIRECT)) != 305 (IO_VMIO | IO_DIRECT), 306 ("IO_DIRECT used for a cache flush?")); 307 /* Invalidate the write cache when writing directly */ 308 err = fuse_inval_buf_range(vp, filesize, start, end); 309 if (err) 310 return (err); 311 err = fuse_write_directbackend(vp, uio, cred, fufh, 312 filesize, ioflag, false); 313 } else { 314 SDT_PROBE2(fusefs, , io, trace, 1, 315 "buffered write of vnode"); 316 if (!fsess_opt_writeback(vnode_mount(vp))) 317 ioflag |= IO_SYNC; 318 err = fuse_write_biobackend(vp, uio, cred, fufh, ioflag, 319 pid); 320 } 321 fuse_io_clear_suid_on_write(vp, cred, uio->uio_td); 322 break; 323 default: 324 panic("uninterpreted mode passed to fuse_io_dispatch"); 325 } 326 327 out: 328 if (closefufh) 329 fuse_filehandle_close(vp, fufh, curthread, cred); 330 331 return (err); 332 } 333 334 SDT_PROBE_DEFINE4(fusefs, , io, read_bio_backend_start, "int", "int", "int", "int"); 335 SDT_PROBE_DEFINE2(fusefs, , io, read_bio_backend_feed, "int", "struct buf*"); 336 SDT_PROBE_DEFINE4(fusefs, , io, read_bio_backend_end, "int", "ssize_t", "int", 337 "struct buf*"); 338 static int 339 fuse_read_biobackend(struct vnode *vp, struct uio *uio, int ioflag, 340 struct ucred *cred, struct fuse_filehandle *fufh, pid_t pid) 341 { 342 struct buf *bp; 343 struct mount *mp; 344 struct fuse_data *data; 345 daddr_t lbn, nextlbn; 346 int bcount, nextsize; 347 int err, n = 0, on = 0, seqcount; 348 off_t filesize; 349 350 const int biosize = fuse_iosize(vp); 351 mp = vnode_mount(vp); 352 data = fuse_get_mpdata(mp); 353 354 if (uio->uio_offset < 0) 355 return (EINVAL); 356 357 seqcount = ioflag >> IO_SEQSHIFT; 358 359 err = fuse_vnode_size(vp, &filesize, cred, curthread); 360 if (err) 361 return err; 362 363 for (err = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { 364 if (fuse_isdeadfs(vp)) { 365 err = ENXIO; 366 break; 367 } 368 if (filesize - uio->uio_offset <= 0) 369 break; 370 lbn = uio->uio_offset / biosize; 371 on = uio->uio_offset & (biosize - 1); 372 373 if ((off_t)lbn * biosize >= filesize) { 374 bcount = 0; 375 } else if ((off_t)(lbn + 1) * biosize > filesize) { 376 bcount = filesize - (off_t)lbn *biosize; 377 } else { 378 bcount = biosize; 379 } 380 nextlbn = lbn + 1; 381 nextsize = MIN(biosize, filesize - nextlbn * biosize); 382 383 SDT_PROBE4(fusefs, , io, read_bio_backend_start, 384 biosize, (int)lbn, on, bcount); 385 386 if (bcount < biosize) { 387 /* If near EOF, don't do readahead */ 388 err = bread(vp, lbn, bcount, NOCRED, &bp); 389 } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) { 390 /* Try clustered read */ 391 long totread = uio->uio_resid + on; 392 seqcount = MIN(seqcount, 393 data->max_readahead_blocks + 1); 394 err = cluster_read(vp, filesize, lbn, bcount, NOCRED, 395 totread, seqcount, 0, &bp); 396 } else if (seqcount > 1 && data->max_readahead_blocks >= 1) { 397 /* Try non-clustered readahead */ 398 err = breadn(vp, lbn, bcount, &nextlbn, &nextsize, 1, 399 NOCRED, &bp); 400 } else { 401 /* Just read what was requested */ 402 err = bread(vp, lbn, bcount, NOCRED, &bp); 403 } 404 405 if (err) { 406 brelse(bp); 407 bp = NULL; 408 break; 409 } 410 411 /* 412 * on is the offset into the current bp. Figure out how many 413 * bytes we can copy out of the bp. Note that bcount is 414 * NOT DEV_BSIZE aligned. 415 * 416 * Then figure out how many bytes we can copy into the uio. 417 */ 418 419 n = 0; 420 if (on < bcount - bp->b_resid) 421 n = MIN((unsigned)(bcount - bp->b_resid - on), 422 uio->uio_resid); 423 if (n > 0) { 424 SDT_PROBE2(fusefs, , io, read_bio_backend_feed, n, bp); 425 err = uiomove(bp->b_data + on, n, uio); 426 } 427 vfs_bio_brelse(bp, ioflag); 428 SDT_PROBE4(fusefs, , io, read_bio_backend_end, err, 429 uio->uio_resid, n, bp); 430 if (bp->b_resid > 0) { 431 /* Short read indicates EOF */ 432 break; 433 } 434 } 435 436 return (err); 437 } 438 439 SDT_PROBE_DEFINE1(fusefs, , io, read_directbackend_start, 440 "struct fuse_read_in*"); 441 SDT_PROBE_DEFINE3(fusefs, , io, read_directbackend_complete, 442 "struct fuse_dispatcher*", "struct fuse_read_in*", "struct uio*"); 443 444 static int 445 fuse_read_directbackend(struct vnode *vp, struct uio *uio, 446 struct ucred *cred, struct fuse_filehandle *fufh) 447 { 448 struct fuse_data *data; 449 struct fuse_dispatcher fdi; 450 struct fuse_read_in *fri; 451 int err = 0; 452 453 data = fuse_get_mpdata(vp->v_mount); 454 455 if (uio->uio_resid == 0) 456 return (0); 457 458 fdisp_init(&fdi, 0); 459 460 /* 461 * XXX In "normal" case we use an intermediate kernel buffer for 462 * transmitting data from daemon's context to ours. Eventually, we should 463 * get rid of this. Anyway, if the target uio lives in sysspace (we are 464 * called from pageops), and the input data doesn't need kernel-side 465 * processing (we are not called from readdir) we can already invoke 466 * an optimized, "peer-to-peer" I/O routine. 467 */ 468 while (uio->uio_resid > 0) { 469 fdi.iosize = sizeof(*fri); 470 fdisp_make_vp(&fdi, FUSE_READ, vp, uio->uio_td, cred); 471 fri = fdi.indata; 472 fri->fh = fufh->fh_id; 473 fri->offset = uio->uio_offset; 474 fri->size = MIN(uio->uio_resid, 475 fuse_get_mpdata(vp->v_mount)->max_read); 476 if (fuse_libabi_geq(data, 7, 9)) { 477 /* See comment regarding FUSE_WRITE_LOCKOWNER */ 478 fri->read_flags = 0; 479 fri->flags = fufh_type_2_fflags(fufh->fufh_type); 480 } 481 482 SDT_PROBE1(fusefs, , io, read_directbackend_start, fri); 483 484 if ((err = fdisp_wait_answ(&fdi))) 485 goto out; 486 487 SDT_PROBE3(fusefs, , io, read_directbackend_complete, 488 &fdi, fri, uio); 489 490 if ((err = uiomove(fdi.answ, MIN(fri->size, fdi.iosize), uio))) 491 break; 492 if (fdi.iosize < fri->size) { 493 /* 494 * Short read. Should only happen at EOF or with 495 * direct io. 496 */ 497 break; 498 } 499 } 500 501 out: 502 fdisp_destroy(&fdi); 503 return (err); 504 } 505 506 static int 507 fuse_write_directbackend(struct vnode *vp, struct uio *uio, 508 struct ucred *cred, struct fuse_filehandle *fufh, off_t filesize, 509 int ioflag, bool pages) 510 { 511 struct fuse_vnode_data *fvdat = VTOFUD(vp); 512 struct fuse_data *data; 513 struct fuse_write_in *fwi; 514 struct fuse_write_out *fwo; 515 struct fuse_dispatcher fdi; 516 size_t chunksize; 517 void *fwi_data; 518 off_t as_written_offset; 519 int diff; 520 int err = 0; 521 bool direct_io = fufh->fuse_open_flags & FOPEN_DIRECT_IO; 522 bool wrote_anything = false; 523 uint32_t write_flags; 524 525 data = fuse_get_mpdata(vp->v_mount); 526 527 /* 528 * Don't set FUSE_WRITE_LOCKOWNER in write_flags. It can't be set 529 * accurately when using POSIX AIO, libfuse doesn't use it, and I'm not 530 * aware of any file systems that do. It was an attempt to add 531 * Linux-style mandatory locking to the FUSE protocol, but mandatory 532 * locking is deprecated even on Linux. See Linux commit 533 * f33321141b273d60cbb3a8f56a5489baad82ba5e . 534 */ 535 /* 536 * Set FUSE_WRITE_CACHE whenever we don't know the uid, gid, and/or pid 537 * that originated a write. For example when writing from the 538 * writeback cache. I don't know of a single file system that cares, 539 * but the protocol says we're supposed to do this. 540 */ 541 write_flags = !pages && ( 542 (ioflag & IO_DIRECT) || 543 !fsess_opt_datacache(vnode_mount(vp)) || 544 !fsess_opt_writeback(vnode_mount(vp))) ? 0 : FUSE_WRITE_CACHE; 545 546 if (uio->uio_resid == 0) 547 return (0); 548 549 if (ioflag & IO_APPEND) 550 uio_setoffset(uio, filesize); 551 552 if (vn_rlimit_fsize(vp, uio, uio->uio_td)) 553 return (EFBIG); 554 555 fdisp_init(&fdi, 0); 556 557 while (uio->uio_resid > 0) { 558 size_t sizeof_fwi; 559 560 if (fuse_libabi_geq(data, 7, 9)) { 561 sizeof_fwi = sizeof(*fwi); 562 } else { 563 sizeof_fwi = FUSE_COMPAT_WRITE_IN_SIZE; 564 } 565 566 chunksize = MIN(uio->uio_resid, data->max_write); 567 568 fdi.iosize = sizeof_fwi + chunksize; 569 fdisp_make_vp(&fdi, FUSE_WRITE, vp, uio->uio_td, cred); 570 571 fwi = fdi.indata; 572 fwi->fh = fufh->fh_id; 573 fwi->offset = uio->uio_offset; 574 fwi->size = chunksize; 575 fwi->write_flags = write_flags; 576 if (fuse_libabi_geq(data, 7, 9)) { 577 fwi->flags = fufh_type_2_fflags(fufh->fufh_type); 578 } 579 fwi_data = (char *)fdi.indata + sizeof_fwi; 580 581 if ((err = uiomove(fwi_data, chunksize, uio))) 582 break; 583 584 retry: 585 err = fdisp_wait_answ(&fdi); 586 if (err == ERESTART || err == EINTR || err == EWOULDBLOCK) { 587 /* 588 * Rewind the uio so dofilewrite will know it's 589 * incomplete 590 */ 591 uio->uio_resid += fwi->size; 592 uio->uio_offset -= fwi->size; 593 /* 594 * Change ERESTART into EINTR because we can't rewind 595 * uio->uio_iov. Basically, once uiomove(9) has been 596 * called, it's impossible to restart a syscall. 597 */ 598 if (err == ERESTART) 599 err = EINTR; 600 break; 601 } else if (err) { 602 break; 603 } else { 604 wrote_anything = true; 605 } 606 607 fwo = ((struct fuse_write_out *)fdi.answ); 608 609 /* Adjust the uio in the case of short writes */ 610 diff = fwi->size - fwo->size; 611 as_written_offset = uio->uio_offset - diff; 612 613 if (as_written_offset - diff > filesize) 614 fuse_vnode_setsize(vp, as_written_offset); 615 if (as_written_offset - diff >= filesize) 616 fvdat->flag &= ~FN_SIZECHANGE; 617 618 if (diff < 0) { 619 printf("WARNING: misbehaving FUSE filesystem " 620 "wrote more data than we provided it\n"); 621 err = EINVAL; 622 break; 623 } else if (diff > 0) { 624 /* Short write */ 625 if (!direct_io) { 626 printf("WARNING: misbehaving FUSE filesystem: " 627 "short writes are only allowed with " 628 "direct_io\n"); 629 } 630 if (ioflag & IO_DIRECT) { 631 /* Return early */ 632 uio->uio_resid += diff; 633 uio->uio_offset -= diff; 634 break; 635 } else { 636 /* Resend the unwritten portion of data */ 637 fdi.iosize = sizeof_fwi + diff; 638 /* Refresh fdi without clearing data buffer */ 639 fdisp_refresh_vp(&fdi, FUSE_WRITE, vp, 640 uio->uio_td, cred); 641 fwi = fdi.indata; 642 MPASS2(fwi == fdi.indata, "FUSE dispatcher " 643 "reallocated despite no increase in " 644 "size?"); 645 void *src = (char*)fwi_data + fwo->size; 646 memmove(fwi_data, src, diff); 647 fwi->fh = fufh->fh_id; 648 fwi->offset = as_written_offset; 649 fwi->size = diff; 650 fwi->write_flags = write_flags; 651 goto retry; 652 } 653 } 654 } 655 656 fdisp_destroy(&fdi); 657 658 if (wrote_anything) 659 fuse_vnode_undirty_cached_timestamps(vp); 660 661 return (err); 662 } 663 664 SDT_PROBE_DEFINE6(fusefs, , io, write_biobackend_start, "int64_t", "int", "int", 665 "struct uio*", "int", "bool"); 666 SDT_PROBE_DEFINE2(fusefs, , io, write_biobackend_append_race, "long", "int"); 667 SDT_PROBE_DEFINE2(fusefs, , io, write_biobackend_issue, "int", "struct buf*"); 668 669 static int 670 fuse_write_biobackend(struct vnode *vp, struct uio *uio, 671 struct ucred *cred, struct fuse_filehandle *fufh, int ioflag, pid_t pid) 672 { 673 struct fuse_vnode_data *fvdat = VTOFUD(vp); 674 struct buf *bp; 675 daddr_t lbn; 676 off_t filesize; 677 int bcount; 678 int n, on, seqcount, err = 0; 679 bool last_page; 680 681 const int biosize = fuse_iosize(vp); 682 683 seqcount = ioflag >> IO_SEQSHIFT; 684 685 KASSERT(uio->uio_rw == UIO_WRITE, ("fuse_write_biobackend mode")); 686 if (vp->v_type != VREG) 687 return (EIO); 688 if (uio->uio_offset < 0) 689 return (EINVAL); 690 if (uio->uio_resid == 0) 691 return (0); 692 693 err = fuse_vnode_size(vp, &filesize, cred, curthread); 694 if (err) 695 return err; 696 697 if (ioflag & IO_APPEND) 698 uio_setoffset(uio, filesize); 699 700 if (vn_rlimit_fsize(vp, uio, uio->uio_td)) 701 return (EFBIG); 702 703 do { 704 bool direct_append, extending; 705 706 if (fuse_isdeadfs(vp)) { 707 err = ENXIO; 708 break; 709 } 710 lbn = uio->uio_offset / biosize; 711 on = uio->uio_offset & (biosize - 1); 712 n = MIN((unsigned)(biosize - on), uio->uio_resid); 713 714 again: 715 /* Get or create a buffer for the write */ 716 direct_append = uio->uio_offset == filesize && n; 717 if (uio->uio_offset + n < filesize) { 718 extending = false; 719 if ((off_t)(lbn + 1) * biosize < filesize) { 720 /* Not the file's last block */ 721 bcount = biosize; 722 } else { 723 /* The file's last block */ 724 bcount = filesize - (off_t)lbn * biosize; 725 } 726 } else { 727 extending = true; 728 bcount = on + n; 729 } 730 if (howmany(((off_t)lbn * biosize + on + n - 1), PAGE_SIZE) >= 731 howmany(filesize, PAGE_SIZE)) 732 last_page = true; 733 else 734 last_page = false; 735 if (direct_append) { 736 /* 737 * Take care to preserve the buffer's B_CACHE state so 738 * as not to cause an unnecessary read. 739 */ 740 bp = getblk(vp, lbn, on, PCATCH, 0, 0); 741 if (bp != NULL) { 742 uint32_t save = bp->b_flags & B_CACHE; 743 allocbuf(bp, bcount); 744 bp->b_flags |= save; 745 } 746 } else { 747 bp = getblk(vp, lbn, bcount, PCATCH, 0, 0); 748 } 749 if (!bp) { 750 err = EINTR; 751 break; 752 } 753 if (extending) { 754 /* 755 * Extend file _after_ locking buffer so we won't race 756 * with other readers 757 */ 758 err = fuse_vnode_setsize(vp, uio->uio_offset + n); 759 filesize = uio->uio_offset + n; 760 fvdat->flag |= FN_SIZECHANGE; 761 if (err) { 762 brelse(bp); 763 break; 764 } 765 } 766 767 SDT_PROBE6(fusefs, , io, write_biobackend_start, 768 lbn, on, n, uio, bcount, direct_append); 769 /* 770 * Issue a READ if B_CACHE is not set. In special-append 771 * mode, B_CACHE is based on the buffer prior to the write 772 * op and is typically set, avoiding the read. If a read 773 * is required in special append mode, the server will 774 * probably send us a short-read since we extended the file 775 * on our end, resulting in b_resid == 0 and, thusly, 776 * B_CACHE getting set. 777 * 778 * We can also avoid issuing the read if the write covers 779 * the entire buffer. We have to make sure the buffer state 780 * is reasonable in this case since we will not be initiating 781 * I/O. See the comments in kern/vfs_bio.c's getblk() for 782 * more information. 783 * 784 * B_CACHE may also be set due to the buffer being cached 785 * normally. 786 */ 787 788 if (on == 0 && n == bcount) { 789 bp->b_flags |= B_CACHE; 790 bp->b_flags &= ~B_INVAL; 791 bp->b_ioflags &= ~BIO_ERROR; 792 } 793 if ((bp->b_flags & B_CACHE) == 0) { 794 bp->b_iocmd = BIO_READ; 795 vfs_busy_pages(bp, 0); 796 fuse_io_strategy(vp, bp); 797 if ((err = bp->b_error)) { 798 brelse(bp); 799 break; 800 } 801 if (bp->b_resid > 0) { 802 /* 803 * Short read indicates EOF. Update file size 804 * from the server and try again. 805 */ 806 SDT_PROBE2(fusefs, , io, trace, 1, 807 "Short read during a RMW"); 808 brelse(bp); 809 err = fuse_vnode_size(vp, &filesize, cred, 810 curthread); 811 if (err) 812 break; 813 else 814 goto again; 815 } 816 } 817 if (bp->b_wcred == NOCRED) 818 bp->b_wcred = crhold(cred); 819 820 /* 821 * If dirtyend exceeds file size, chop it down. This should 822 * not normally occur but there is an append race where it 823 * might occur XXX, so we log it. 824 * 825 * If the chopping creates a reverse-indexed or degenerate 826 * situation with dirtyoff/end, we 0 both of them. 827 */ 828 if (bp->b_dirtyend > bcount) { 829 SDT_PROBE2(fusefs, , io, write_biobackend_append_race, 830 (long)bp->b_blkno * biosize, 831 bp->b_dirtyend - bcount); 832 bp->b_dirtyend = bcount; 833 } 834 if (bp->b_dirtyoff >= bp->b_dirtyend) 835 bp->b_dirtyoff = bp->b_dirtyend = 0; 836 837 /* 838 * If the new write will leave a contiguous dirty 839 * area, just update the b_dirtyoff and b_dirtyend, 840 * otherwise force a write rpc of the old dirty area. 841 * 842 * While it is possible to merge discontiguous writes due to 843 * our having a B_CACHE buffer ( and thus valid read data 844 * for the hole), we don't because it could lead to 845 * significant cache coherency problems with multiple clients, 846 * especially if locking is implemented later on. 847 * 848 * as an optimization we could theoretically maintain 849 * a linked list of discontinuous areas, but we would still 850 * have to commit them separately so there isn't much 851 * advantage to it except perhaps a bit of asynchronization. 852 */ 853 854 if (bp->b_dirtyend > 0 && 855 (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) { 856 /* 857 * Yes, we mean it. Write out everything to "storage" 858 * immediately, without hesitation. (Apart from other 859 * reasons: the only way to know if a write is valid 860 * if its actually written out.) 861 */ 862 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 0, bp); 863 bwrite(bp); 864 if (bp->b_error == EINTR) { 865 err = EINTR; 866 break; 867 } 868 goto again; 869 } 870 err = uiomove((char *)bp->b_data + on, n, uio); 871 872 if (err) { 873 bp->b_ioflags |= BIO_ERROR; 874 bp->b_error = err; 875 brelse(bp); 876 break; 877 /* TODO: vfs_bio_clrbuf like ffs_write does? */ 878 } 879 /* 880 * Only update dirtyoff/dirtyend if not a degenerate 881 * condition. 882 */ 883 if (n) { 884 if (bp->b_dirtyend > 0) { 885 bp->b_dirtyoff = MIN(on, bp->b_dirtyoff); 886 bp->b_dirtyend = MAX((on + n), bp->b_dirtyend); 887 } else { 888 bp->b_dirtyoff = on; 889 bp->b_dirtyend = on + n; 890 } 891 vfs_bio_set_valid(bp, on, n); 892 } 893 894 vfs_bio_set_flags(bp, ioflag); 895 896 bp->b_flags |= B_FUSEFS_WRITE_CACHE; 897 if (ioflag & IO_SYNC) { 898 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 2, bp); 899 if (!(ioflag & IO_VMIO)) 900 bp->b_flags &= ~B_FUSEFS_WRITE_CACHE; 901 err = bwrite(bp); 902 } else if (vm_page_count_severe() || 903 buf_dirty_count_severe() || 904 (ioflag & IO_ASYNC)) { 905 bp->b_flags |= B_CLUSTEROK; 906 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 3, bp); 907 bawrite(bp); 908 } else if (on == 0 && n == bcount) { 909 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) { 910 bp->b_flags |= B_CLUSTEROK; 911 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 912 4, bp); 913 cluster_write(vp, bp, filesize, seqcount, 0); 914 } else { 915 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 916 5, bp); 917 bawrite(bp); 918 } 919 } else if (ioflag & IO_DIRECT) { 920 bp->b_flags |= B_CLUSTEROK; 921 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 6, bp); 922 bawrite(bp); 923 } else { 924 bp->b_flags &= ~B_CLUSTEROK; 925 SDT_PROBE2(fusefs, , io, write_biobackend_issue, 7, bp); 926 bdwrite(bp); 927 } 928 if (err) 929 break; 930 } while (uio->uio_resid > 0 && n > 0); 931 932 return (err); 933 } 934 935 int 936 fuse_io_strategy(struct vnode *vp, struct buf *bp) 937 { 938 struct fuse_vnode_data *fvdat = VTOFUD(vp); 939 struct fuse_filehandle *fufh; 940 struct ucred *cred; 941 struct uio *uiop; 942 struct uio uio; 943 struct iovec io; 944 off_t filesize; 945 int error = 0; 946 int fflag; 947 /* We don't know the true pid when we're dealing with the cache */ 948 pid_t pid = 0; 949 950 const int biosize = fuse_iosize(vp); 951 952 MPASS(vp->v_type == VREG || vp->v_type == VDIR); 953 MPASS(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE); 954 955 fflag = bp->b_iocmd == BIO_READ ? FREAD : FWRITE; 956 cred = bp->b_iocmd == BIO_READ ? bp->b_rcred : bp->b_wcred; 957 error = fuse_filehandle_getrw(vp, fflag, &fufh, cred, pid); 958 if (bp->b_iocmd == BIO_READ && error == EBADF) { 959 /* 960 * This may be a read-modify-write operation on a cached file 961 * opened O_WRONLY. The FUSE protocol allows this. 962 */ 963 error = fuse_filehandle_get(vp, FWRITE, &fufh, cred, pid); 964 } 965 if (error) { 966 printf("FUSE: strategy: filehandles are closed\n"); 967 bp->b_ioflags |= BIO_ERROR; 968 bp->b_error = error; 969 bufdone(bp); 970 return (error); 971 } 972 973 uiop = &uio; 974 uiop->uio_iov = &io; 975 uiop->uio_iovcnt = 1; 976 uiop->uio_segflg = UIO_SYSSPACE; 977 uiop->uio_td = curthread; 978 979 /* 980 * clear BIO_ERROR and B_INVAL state prior to initiating the I/O. We 981 * do this here so we do not have to do it in all the code that 982 * calls us. 983 */ 984 bp->b_flags &= ~B_INVAL; 985 bp->b_ioflags &= ~BIO_ERROR; 986 987 KASSERT(!(bp->b_flags & B_DONE), 988 ("fuse_io_strategy: bp %p already marked done", bp)); 989 if (bp->b_iocmd == BIO_READ) { 990 ssize_t left; 991 992 io.iov_len = uiop->uio_resid = bp->b_bcount; 993 io.iov_base = bp->b_data; 994 uiop->uio_rw = UIO_READ; 995 996 uiop->uio_offset = ((off_t)bp->b_lblkno) * biosize; 997 error = fuse_read_directbackend(vp, uiop, cred, fufh); 998 /* 999 * Store the amount we failed to read in the buffer's private 1000 * field, so callers can truncate the file if necessary' 1001 */ 1002 1003 if (!error && uiop->uio_resid) { 1004 int nread = bp->b_bcount - uiop->uio_resid; 1005 left = uiop->uio_resid; 1006 bzero((char *)bp->b_data + nread, left); 1007 1008 if ((fvdat->flag & FN_SIZECHANGE) == 0) { 1009 /* 1010 * A short read with no error, when not using 1011 * direct io, and when no writes are cached, 1012 * indicates EOF caused by a server-side 1013 * truncation. Clear the attr cache so we'll 1014 * pick up the new file size and timestamps. 1015 * 1016 * We must still bzero the remaining buffer so 1017 * uninitialized data doesn't get exposed by a 1018 * future truncate that extends the file. 1019 * 1020 * To prevent lock order problems, we must 1021 * truncate the file upstack, not here. 1022 */ 1023 SDT_PROBE2(fusefs, , io, trace, 1, 1024 "Short read of a clean file"); 1025 fuse_vnode_clear_attr_cache(vp); 1026 } else { 1027 /* 1028 * If dirty writes _are_ cached beyond EOF, 1029 * that indicates a newly created hole that the 1030 * server doesn't know about. Those don't pose 1031 * any problem. 1032 * XXX: we don't currently track whether dirty 1033 * writes are cached beyond EOF, before EOF, or 1034 * both. 1035 */ 1036 SDT_PROBE2(fusefs, , io, trace, 1, 1037 "Short read of a dirty file"); 1038 uiop->uio_resid = 0; 1039 } 1040 1041 } 1042 if (error) { 1043 bp->b_ioflags |= BIO_ERROR; 1044 bp->b_error = error; 1045 } 1046 } else { 1047 /* 1048 * Setup for actual write 1049 */ 1050 error = fuse_vnode_size(vp, &filesize, cred, curthread); 1051 if (error) { 1052 bp->b_ioflags |= BIO_ERROR; 1053 bp->b_error = error; 1054 bufdone(bp); 1055 return (error); 1056 } 1057 1058 if ((off_t)bp->b_lblkno * biosize + bp->b_dirtyend > filesize) 1059 bp->b_dirtyend = filesize - 1060 (off_t)bp->b_lblkno * biosize; 1061 1062 if (bp->b_dirtyend > bp->b_dirtyoff) { 1063 io.iov_len = uiop->uio_resid = bp->b_dirtyend 1064 - bp->b_dirtyoff; 1065 uiop->uio_offset = (off_t)bp->b_lblkno * biosize 1066 + bp->b_dirtyoff; 1067 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff; 1068 uiop->uio_rw = UIO_WRITE; 1069 1070 bool pages = bp->b_flags & B_FUSEFS_WRITE_CACHE; 1071 error = fuse_write_directbackend(vp, uiop, cred, fufh, 1072 filesize, 0, pages); 1073 1074 if (error == EINTR || error == ETIMEDOUT) { 1075 bp->b_flags &= ~(B_INVAL | B_NOCACHE); 1076 if ((bp->b_flags & B_PAGING) == 0) { 1077 bdirty(bp); 1078 bp->b_flags &= ~B_DONE; 1079 } 1080 if ((error == EINTR || error == ETIMEDOUT) && 1081 (bp->b_flags & B_ASYNC) == 0) 1082 bp->b_flags |= B_EINTR; 1083 } else { 1084 if (error) { 1085 bp->b_ioflags |= BIO_ERROR; 1086 bp->b_flags |= B_INVAL; 1087 bp->b_error = error; 1088 } 1089 bp->b_dirtyoff = bp->b_dirtyend = 0; 1090 } 1091 } else { 1092 bp->b_resid = 0; 1093 bufdone(bp); 1094 return (0); 1095 } 1096 } 1097 bp->b_resid = uiop->uio_resid; 1098 bufdone(bp); 1099 return (error); 1100 } 1101 1102 int 1103 fuse_io_flushbuf(struct vnode *vp, int waitfor, struct thread *td) 1104 { 1105 1106 return (vn_fsync_buf(vp, waitfor)); 1107 } 1108 1109 /* 1110 * Flush and invalidate all dirty buffers. If another process is already 1111 * doing the flush, just wait for completion. 1112 */ 1113 int 1114 fuse_io_invalbuf(struct vnode *vp, struct thread *td) 1115 { 1116 struct fuse_vnode_data *fvdat = VTOFUD(vp); 1117 int error = 0; 1118 1119 if (VN_IS_DOOMED(vp)) 1120 return 0; 1121 1122 ASSERT_VOP_ELOCKED(vp, "fuse_io_invalbuf"); 1123 1124 while (fvdat->flag & FN_FLUSHINPROG) { 1125 struct proc *p = td->td_proc; 1126 1127 if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) 1128 return EIO; 1129 fvdat->flag |= FN_FLUSHWANT; 1130 tsleep(&fvdat->flag, PRIBIO + 2, "fusevinv", 2 * hz); 1131 error = 0; 1132 if (p != NULL) { 1133 PROC_LOCK(p); 1134 if (SIGNOTEMPTY(p->p_siglist) || 1135 SIGNOTEMPTY(td->td_siglist)) 1136 error = EINTR; 1137 PROC_UNLOCK(p); 1138 } 1139 if (error == EINTR) 1140 return EINTR; 1141 } 1142 fvdat->flag |= FN_FLUSHINPROG; 1143 1144 if (vp->v_bufobj.bo_object != NULL) { 1145 VM_OBJECT_WLOCK(vp->v_bufobj.bo_object); 1146 vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC); 1147 VM_OBJECT_WUNLOCK(vp->v_bufobj.bo_object); 1148 } 1149 error = vinvalbuf(vp, V_SAVE, PCATCH, 0); 1150 while (error) { 1151 if (error == ERESTART || error == EINTR) { 1152 fvdat->flag &= ~FN_FLUSHINPROG; 1153 if (fvdat->flag & FN_FLUSHWANT) { 1154 fvdat->flag &= ~FN_FLUSHWANT; 1155 wakeup(&fvdat->flag); 1156 } 1157 return EINTR; 1158 } 1159 error = vinvalbuf(vp, V_SAVE, PCATCH, 0); 1160 } 1161 fvdat->flag &= ~FN_FLUSHINPROG; 1162 if (fvdat->flag & FN_FLUSHWANT) { 1163 fvdat->flag &= ~FN_FLUSHWANT; 1164 wakeup(&fvdat->flag); 1165 } 1166 return (error); 1167 } 1168