/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 2007-2009 Google Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * Copyright (C) 2005 Csaba Henk. * All rights reserved. * * Copyright (c) 2019 The FreeBSD Foundation * * Portions of this software were developed by BFF Storage Systems, LLC under * sponsorship from the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "fuse.h" #include "fuse_file.h" #include "fuse_node.h" #include "fuse_internal.h" #include "fuse_ipc.h" #include "fuse_io.h" /* * Set in a struct buf to indicate that the write came from the buffer cache * and the originating cred and pid are no longer known. */ #define B_FUSEFS_WRITE_CACHE B_FS_FLAG1 SDT_PROVIDER_DECLARE(fusefs); /* * Fuse trace probe: * arg0: verbosity. Higher numbers give more verbose messages * arg1: Textual message */ SDT_PROBE_DEFINE2(fusefs, , io, trace, "int", "char*"); SDT_PROBE_DEFINE4(fusefs, , io, read_bio_backend_start, "int", "int", "int", "int"); SDT_PROBE_DEFINE2(fusefs, , io, read_bio_backend_feed, "int", "struct buf*"); SDT_PROBE_DEFINE4(fusefs, , io, read_bio_backend_end, "int", "ssize_t", "int", "struct buf*"); int fuse_read_biobackend(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred, struct fuse_filehandle *fufh, pid_t pid) { struct buf *bp; struct mount *mp; struct fuse_data *data; daddr_t lbn, nextlbn; int bcount, nextsize; int err, n = 0, on = 0, seqcount; off_t filesize; const int biosize = fuse_iosize(vp); mp = vnode_mount(vp); data = fuse_get_mpdata(mp); if (uio->uio_offset < 0) return (EINVAL); seqcount = ioflag >> IO_SEQSHIFT; err = fuse_vnode_size(vp, &filesize, cred, curthread); if (err) return err; for (err = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { if (fuse_isdeadfs(vp)) { err = ENXIO; break; } if (filesize - uio->uio_offset <= 0) break; lbn = uio->uio_offset / biosize; on = uio->uio_offset & (biosize - 1); if ((off_t)lbn * biosize >= filesize) { bcount = 0; } else if ((off_t)(lbn + 1) * biosize > filesize) { bcount = filesize - (off_t)lbn *biosize; } else { bcount = biosize; } nextlbn = lbn + 1; nextsize = MIN(biosize, filesize - nextlbn * biosize); SDT_PROBE4(fusefs, , io, read_bio_backend_start, biosize, (int)lbn, on, bcount); if (bcount < biosize) { /* If near EOF, don't do readahead */ err = bread(vp, lbn, bcount, NOCRED, &bp); } else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) { /* Try clustered read */ long totread = uio->uio_resid + on; seqcount = MIN(seqcount, data->max_readahead_blocks + 1); err = cluster_read(vp, filesize, lbn, bcount, NOCRED, totread, seqcount, 0, &bp); } else if (seqcount > 1 && data->max_readahead_blocks >= 1) { /* Try non-clustered readahead */ err = breadn(vp, lbn, bcount, &nextlbn, &nextsize, 1, NOCRED, &bp); } else { /* Just read what was requested */ err = bread(vp, lbn, bcount, NOCRED, &bp); } if (err) { brelse(bp); bp = NULL; break; } /* * on is the offset into the current bp. Figure out how many * bytes we can copy out of the bp. Note that bcount is * NOT DEV_BSIZE aligned. * * Then figure out how many bytes we can copy into the uio. */ n = 0; if (on < bcount - bp->b_resid) n = MIN((unsigned)(bcount - bp->b_resid - on), uio->uio_resid); if (n > 0) { SDT_PROBE2(fusefs, , io, read_bio_backend_feed, n, bp); err = uiomove(bp->b_data + on, n, uio); } vfs_bio_brelse(bp, ioflag); SDT_PROBE4(fusefs, , io, read_bio_backend_end, err, uio->uio_resid, n, bp); if (bp->b_resid > 0) { /* Short read indicates EOF */ break; } } return (err); } SDT_PROBE_DEFINE1(fusefs, , io, read_directbackend_start, "struct fuse_read_in*"); SDT_PROBE_DEFINE3(fusefs, , io, read_directbackend_complete, "struct fuse_dispatcher*", "struct fuse_read_in*", "struct uio*"); int fuse_read_directbackend(struct vnode *vp, struct uio *uio, struct ucred *cred, struct fuse_filehandle *fufh) { struct fuse_data *data; struct fuse_dispatcher fdi; struct fuse_read_in *fri; int err = 0; data = fuse_get_mpdata(vp->v_mount); if (uio->uio_resid == 0) return (0); fdisp_init(&fdi, 0); /* * XXX In "normal" case we use an intermediate kernel buffer for * transmitting data from daemon's context to ours. Eventually, we should * get rid of this. Anyway, if the target uio lives in sysspace (we are * called from pageops), and the input data doesn't need kernel-side * processing (we are not called from readdir) we can already invoke * an optimized, "peer-to-peer" I/O routine. */ while (uio->uio_resid > 0) { fdi.iosize = sizeof(*fri); fdisp_make_vp(&fdi, FUSE_READ, vp, uio->uio_td, cred); fri = fdi.indata; fri->fh = fufh->fh_id; fri->offset = uio->uio_offset; fri->size = MIN(uio->uio_resid, fuse_get_mpdata(vp->v_mount)->max_read); if (fuse_libabi_geq(data, 7, 9)) { /* See comment regarding FUSE_WRITE_LOCKOWNER */ fri->read_flags = 0; fri->flags = fufh_type_2_fflags(fufh->fufh_type); } SDT_PROBE1(fusefs, , io, read_directbackend_start, fri); if ((err = fdisp_wait_answ(&fdi))) goto out; SDT_PROBE3(fusefs, , io, read_directbackend_complete, &fdi, fri, uio); if ((err = uiomove(fdi.answ, MIN(fri->size, fdi.iosize), uio))) break; if (fdi.iosize < fri->size) { /* * Short read. Should only happen at EOF or with * direct io. */ break; } } out: fdisp_destroy(&fdi); return (err); } int fuse_write_directbackend(struct vnode *vp, struct uio *uio, struct ucred *cred, struct fuse_filehandle *fufh, off_t filesize, int ioflag, bool pages) { struct fuse_vnode_data *fvdat = VTOFUD(vp); struct fuse_data *data; struct fuse_write_in *fwi; struct fuse_write_out *fwo; struct fuse_dispatcher fdi; size_t chunksize; ssize_t r; void *fwi_data; off_t as_written_offset; int diff; int err = 0; bool direct_io = fufh->fuse_open_flags & FOPEN_DIRECT_IO; bool wrote_anything = false; uint32_t write_flags; data = fuse_get_mpdata(vp->v_mount); /* * Don't set FUSE_WRITE_LOCKOWNER in write_flags. It can't be set * accurately when using POSIX AIO, libfuse doesn't use it, and I'm not * aware of any file systems that do. It was an attempt to add * Linux-style mandatory locking to the FUSE protocol, but mandatory * locking is deprecated even on Linux. See Linux commit * f33321141b273d60cbb3a8f56a5489baad82ba5e . */ /* * Set FUSE_WRITE_CACHE whenever we don't know the uid, gid, and/or pid * that originated a write. For example when writing from the * writeback cache. I don't know of a single file system that cares, * but the protocol says we're supposed to do this. */ write_flags = !pages && ( (ioflag & IO_DIRECT) || !fsess_opt_datacache(vnode_mount(vp)) || !fsess_opt_writeback(vnode_mount(vp))) ? 0 : FUSE_WRITE_CACHE; if (uio->uio_resid == 0) return (0); if (ioflag & IO_APPEND) uio_setoffset(uio, filesize); err = vn_rlimit_fsizex(vp, uio, 0, &r, uio->uio_td); if (err != 0) { vn_rlimit_fsizex_res(uio, r); return (err); } fdisp_init(&fdi, 0); while (uio->uio_resid > 0) { size_t sizeof_fwi; if (fuse_libabi_geq(data, 7, 9)) { sizeof_fwi = sizeof(*fwi); } else { sizeof_fwi = FUSE_COMPAT_WRITE_IN_SIZE; } chunksize = MIN(uio->uio_resid, data->max_write); fdi.iosize = sizeof_fwi + chunksize; fdisp_make_vp(&fdi, FUSE_WRITE, vp, uio->uio_td, cred); fwi = fdi.indata; fwi->fh = fufh->fh_id; fwi->offset = uio->uio_offset; fwi->size = chunksize; fwi->write_flags = write_flags; if (fuse_libabi_geq(data, 7, 9)) { fwi->flags = fufh_type_2_fflags(fufh->fufh_type); } fwi_data = (char *)fdi.indata + sizeof_fwi; if ((err = uiomove(fwi_data, chunksize, uio))) break; retry: err = fdisp_wait_answ(&fdi); if (err == ERESTART || err == EINTR || err == EWOULDBLOCK) { /* * Rewind the uio so dofilewrite will know it's * incomplete */ uio->uio_resid += fwi->size; uio->uio_offset -= fwi->size; /* * Change ERESTART into EINTR because we can't rewind * uio->uio_iov. Basically, once uiomove(9) has been * called, it's impossible to restart a syscall. */ if (err == ERESTART) err = EINTR; break; } else if (err) { break; } else { wrote_anything = true; } fwo = ((struct fuse_write_out *)fdi.answ); if (fwo->size > fwi->size) { fuse_warn(data, FSESS_WARN_WROTE_LONG, "wrote more data than we provided it."); /* This is bonkers. Clear attr cache. */ fvdat->flag &= ~FN_SIZECHANGE; fuse_vnode_clear_attr_cache(vp); err = EINVAL; break; } /* Adjust the uio in the case of short writes */ diff = fwi->size - fwo->size; as_written_offset = uio->uio_offset - diff; if (as_written_offset - diff > filesize) { fuse_vnode_setsize(vp, as_written_offset, false); getnanouptime(&fvdat->last_local_modify); } if (as_written_offset - diff >= filesize) fvdat->flag &= ~FN_SIZECHANGE; if (diff > 0) { /* Short write */ if (!direct_io) { fuse_warn(data, FSESS_WARN_SHORT_WRITE, "short writes are only allowed with " "direct_io."); } if (ioflag & IO_DIRECT) { /* Return early */ uio->uio_resid += diff; uio->uio_offset -= diff; break; } else { /* Resend the unwritten portion of data */ fdi.iosize = sizeof_fwi + diff; /* Refresh fdi without clearing data buffer */ fdisp_refresh_vp(&fdi, FUSE_WRITE, vp, uio->uio_td, cred); fwi = fdi.indata; MPASS2(fwi == fdi.indata, "FUSE dispatcher " "reallocated despite no increase in " "size?"); void *src = (char*)fwi_data + fwo->size; memmove(fwi_data, src, diff); fwi->fh = fufh->fh_id; fwi->offset = as_written_offset; fwi->size = diff; fwi->write_flags = write_flags; goto retry; } } } fdisp_destroy(&fdi); if (wrote_anything) fuse_vnode_undirty_cached_timestamps(vp, false); vn_rlimit_fsizex_res(uio, r); return (err); } SDT_PROBE_DEFINE6(fusefs, , io, write_biobackend_start, "int64_t", "int", "int", "struct uio*", "int", "bool"); SDT_PROBE_DEFINE2(fusefs, , io, write_biobackend_append_race, "long", "int"); SDT_PROBE_DEFINE2(fusefs, , io, write_biobackend_issue, "int", "struct buf*"); int fuse_write_biobackend(struct vnode *vp, struct uio *uio, struct ucred *cred, struct fuse_filehandle *fufh, int ioflag, pid_t pid) { struct fuse_vnode_data *fvdat = VTOFUD(vp); struct buf *bp; daddr_t lbn; off_t filesize; ssize_t r; int bcount; int n, on, seqcount, err = 0; const int biosize = fuse_iosize(vp); seqcount = ioflag >> IO_SEQSHIFT; KASSERT(uio->uio_rw == UIO_WRITE, ("fuse_write_biobackend mode")); if (vp->v_type != VREG) return (EIO); if (uio->uio_offset < 0) return (EINVAL); if (uio->uio_resid == 0) return (0); err = fuse_vnode_size(vp, &filesize, cred, curthread); if (err) return err; if (ioflag & IO_APPEND) uio_setoffset(uio, filesize); err = vn_rlimit_fsizex(vp, uio, 0, &r, uio->uio_td); if (err != 0) { vn_rlimit_fsizex_res(uio, r); return (err); } do { bool direct_append, extending; if (fuse_isdeadfs(vp)) { err = ENXIO; break; } lbn = uio->uio_offset / biosize; on = uio->uio_offset & (biosize - 1); n = MIN((unsigned)(biosize - on), uio->uio_resid); again: /* Get or create a buffer for the write */ direct_append = uio->uio_offset == filesize && n; if (uio->uio_offset + n < filesize) { extending = false; if ((off_t)(lbn + 1) * biosize < filesize) { /* Not the file's last block */ bcount = biosize; } else { /* The file's last block */ bcount = filesize - (off_t)lbn * biosize; } } else { extending = true; bcount = on + n; } if (direct_append) { /* * Take care to preserve the buffer's B_CACHE state so * as not to cause an unnecessary read. */ bp = getblk(vp, lbn, on, PCATCH, 0, 0); if (bp != NULL) { uint32_t save = bp->b_flags & B_CACHE; allocbuf(bp, bcount); bp->b_flags |= save; } } else { bp = getblk(vp, lbn, bcount, PCATCH, 0, 0); } if (!bp) { err = EINTR; break; } if (extending) { /* * Extend file _after_ locking buffer so we won't race * with other readers */ err = fuse_vnode_setsize(vp, uio->uio_offset + n, false); filesize = uio->uio_offset + n; getnanouptime(&fvdat->last_local_modify); fvdat->flag |= FN_SIZECHANGE; if (err) { brelse(bp); break; } } SDT_PROBE6(fusefs, , io, write_biobackend_start, lbn, on, n, uio, bcount, direct_append); /* * Issue a READ if B_CACHE is not set. In special-append * mode, B_CACHE is based on the buffer prior to the write * op and is typically set, avoiding the read. If a read * is required in special append mode, the server will * probably send us a short-read since we extended the file * on our end, resulting in b_resid == 0 and, thusly, * B_CACHE getting set. * * We can also avoid issuing the read if the write covers * the entire buffer. We have to make sure the buffer state * is reasonable in this case since we will not be initiating * I/O. See the comments in kern/vfs_bio.c's getblk() for * more information. * * B_CACHE may also be set due to the buffer being cached * normally. */ if (on == 0 && n == bcount) { bp->b_flags |= B_CACHE; bp->b_flags &= ~B_INVAL; bp->b_ioflags &= ~BIO_ERROR; } if ((bp->b_flags & B_CACHE) == 0) { bp->b_iocmd = BIO_READ; vfs_busy_pages(bp, 0); fuse_io_strategy(vp, bp); if ((err = bp->b_error)) { brelse(bp); break; } if (bp->b_resid > 0) { /* * Short read indicates EOF. Update file size * from the server and try again. */ SDT_PROBE2(fusefs, , io, trace, 1, "Short read during a RMW"); brelse(bp); err = fuse_vnode_size(vp, &filesize, cred, curthread); if (err) break; else goto again; } } if (bp->b_wcred == NOCRED) bp->b_wcred = crhold(cred); /* * If dirtyend exceeds file size, chop it down. This should * not normally occur but there is an append race where it * might occur XXX, so we log it. * * If the chopping creates a reverse-indexed or degenerate * situation with dirtyoff/end, we 0 both of them. */ if (bp->b_dirtyend > bcount) { SDT_PROBE2(fusefs, , io, write_biobackend_append_race, (long)bp->b_blkno * biosize, bp->b_dirtyend - bcount); bp->b_dirtyend = bcount; } if (bp->b_dirtyoff >= bp->b_dirtyend) bp->b_dirtyoff = bp->b_dirtyend = 0; /* * If the new write will leave a contiguous dirty * area, just update the b_dirtyoff and b_dirtyend, * otherwise force a write rpc of the old dirty area. * * While it is possible to merge discontiguous writes due to * our having a B_CACHE buffer ( and thus valid read data * for the hole), we don't because it could lead to * significant cache coherency problems with multiple clients, * especially if locking is implemented later on. * * as an optimization we could theoretically maintain * a linked list of discontinuous areas, but we would still * have to commit them separately so there isn't much * advantage to it except perhaps a bit of asynchronization. */ if (bp->b_dirtyend > 0 && (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) { /* * Yes, we mean it. Write out everything to "storage" * immediately, without hesitation. (Apart from other * reasons: the only way to know if a write is valid * if its actually written out.) */ SDT_PROBE2(fusefs, , io, write_biobackend_issue, 0, bp); bwrite(bp); if (bp->b_error == EINTR) { err = EINTR; break; } goto again; } err = uiomove((char *)bp->b_data + on, n, uio); if (err) { bp->b_ioflags |= BIO_ERROR; bp->b_error = err; brelse(bp); break; /* TODO: vfs_bio_clrbuf like ffs_write does? */ } /* * Only update dirtyoff/dirtyend if not a degenerate * condition. */ if (n) { if (bp->b_dirtyend > 0) { bp->b_dirtyoff = MIN(on, bp->b_dirtyoff); bp->b_dirtyend = MAX((on + n), bp->b_dirtyend); } else { bp->b_dirtyoff = on; bp->b_dirtyend = on + n; } vfs_bio_set_valid(bp, on, n); } vfs_bio_set_flags(bp, ioflag); bp->b_flags |= B_FUSEFS_WRITE_CACHE; if (ioflag & IO_SYNC) { SDT_PROBE2(fusefs, , io, write_biobackend_issue, 2, bp); if (!(ioflag & IO_VMIO)) bp->b_flags &= ~B_FUSEFS_WRITE_CACHE; err = bwrite(bp); } else if (vm_page_count_severe() || buf_dirty_count_severe() || (ioflag & IO_ASYNC)) { bp->b_flags |= B_CLUSTEROK; SDT_PROBE2(fusefs, , io, write_biobackend_issue, 3, bp); bawrite(bp); } else if (on == 0 && n == bcount) { if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) { bp->b_flags |= B_CLUSTEROK; SDT_PROBE2(fusefs, , io, write_biobackend_issue, 4, bp); cluster_write(vp, &fvdat->clusterw, bp, filesize, seqcount, 0); } else { SDT_PROBE2(fusefs, , io, write_biobackend_issue, 5, bp); bawrite(bp); } } else if (ioflag & IO_DIRECT) { bp->b_flags |= B_CLUSTEROK; SDT_PROBE2(fusefs, , io, write_biobackend_issue, 6, bp); bawrite(bp); } else { bp->b_flags &= ~B_CLUSTEROK; SDT_PROBE2(fusefs, , io, write_biobackend_issue, 7, bp); bdwrite(bp); } if (err) break; } while (uio->uio_resid > 0 && n > 0); vn_rlimit_fsizex_res(uio, r); return (err); } int fuse_io_strategy(struct vnode *vp, struct buf *bp) { struct fuse_vnode_data *fvdat = VTOFUD(vp); struct fuse_filehandle *fufh; struct ucred *cred; struct uio *uiop; struct uio uio; struct iovec io; off_t filesize; int error = 0; int fflag; /* We don't know the true pid when we're dealing with the cache */ pid_t pid = 0; const int biosize = fuse_iosize(vp); MPASS(vp->v_type == VREG || vp->v_type == VDIR); MPASS(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE); fflag = bp->b_iocmd == BIO_READ ? FREAD : FWRITE; cred = bp->b_iocmd == BIO_READ ? bp->b_rcred : bp->b_wcred; error = fuse_filehandle_getrw(vp, fflag, &fufh, cred, pid); if (bp->b_iocmd == BIO_READ && error == EBADF) { /* * This may be a read-modify-write operation on a cached file * opened O_WRONLY. The FUSE protocol allows this. */ error = fuse_filehandle_get(vp, FWRITE, &fufh, cred, pid); } if (error) { printf("FUSE: strategy: filehandles are closed\n"); bp->b_ioflags |= BIO_ERROR; bp->b_error = error; bufdone(bp); return (error); } uiop = &uio; uiop->uio_iov = &io; uiop->uio_iovcnt = 1; uiop->uio_segflg = UIO_SYSSPACE; uiop->uio_td = curthread; /* * clear BIO_ERROR and B_INVAL state prior to initiating the I/O. We * do this here so we do not have to do it in all the code that * calls us. */ bp->b_flags &= ~B_INVAL; bp->b_ioflags &= ~BIO_ERROR; KASSERT(!(bp->b_flags & B_DONE), ("fuse_io_strategy: bp %p already marked done", bp)); if (bp->b_iocmd == BIO_READ) { ssize_t left; io.iov_len = uiop->uio_resid = bp->b_bcount; io.iov_base = bp->b_data; uiop->uio_rw = UIO_READ; uiop->uio_offset = ((off_t)bp->b_lblkno) * biosize; error = fuse_read_directbackend(vp, uiop, cred, fufh); /* * Store the amount we failed to read in the buffer's private * field, so callers can truncate the file if necessary' */ if (!error && uiop->uio_resid) { int nread = bp->b_bcount - uiop->uio_resid; left = uiop->uio_resid; bzero((char *)bp->b_data + nread, left); if ((fvdat->flag & FN_SIZECHANGE) == 0) { /* * A short read with no error, when not using * direct io, and when no writes are cached, * indicates EOF caused by a server-side * truncation. Clear the attr cache so we'll * pick up the new file size and timestamps. * * We must still bzero the remaining buffer so * uninitialized data doesn't get exposed by a * future truncate that extends the file. * * To prevent lock order problems, we must * truncate the file upstack, not here. */ SDT_PROBE2(fusefs, , io, trace, 1, "Short read of a clean file"); fuse_vnode_clear_attr_cache(vp); } else { /* * If dirty writes _are_ cached beyond EOF, * that indicates a newly created hole that the * server doesn't know about. Those don't pose * any problem. * XXX: we don't currently track whether dirty * writes are cached beyond EOF, before EOF, or * both. */ SDT_PROBE2(fusefs, , io, trace, 1, "Short read of a dirty file"); uiop->uio_resid = 0; } } if (error) { bp->b_ioflags |= BIO_ERROR; bp->b_error = error; } } else { /* * Setup for actual write */ /* * If the file's size is cached, use that value, even if the * cache is expired. At this point we're already committed to * writing something. If the FUSE server has changed the * file's size behind our back, it's too late for us to do * anything about it. In particular, we can't invalidate any * part of the file's buffers because VOP_STRATEGY is called * with them already locked. */ filesize = fvdat->cached_attrs.va_size; /* filesize must've been cached by fuse_vnop_open. */ KASSERT(filesize != VNOVAL, ("filesize should've been cached")); if ((off_t)bp->b_lblkno * biosize + bp->b_dirtyend > filesize) bp->b_dirtyend = filesize - (off_t)bp->b_lblkno * biosize; if (bp->b_dirtyend > bp->b_dirtyoff) { io.iov_len = uiop->uio_resid = bp->b_dirtyend - bp->b_dirtyoff; uiop->uio_offset = (off_t)bp->b_lblkno * biosize + bp->b_dirtyoff; io.iov_base = (char *)bp->b_data + bp->b_dirtyoff; uiop->uio_rw = UIO_WRITE; bool pages = bp->b_flags & B_FUSEFS_WRITE_CACHE; error = fuse_write_directbackend(vp, uiop, cred, fufh, filesize, 0, pages); if (error == EINTR || error == ETIMEDOUT) { bp->b_flags &= ~(B_INVAL | B_NOCACHE); if ((bp->b_flags & B_PAGING) == 0) { bdirty(bp); bp->b_flags &= ~B_DONE; } if ((error == EINTR || error == ETIMEDOUT) && (bp->b_flags & B_ASYNC) == 0) bp->b_flags |= B_EINTR; } else { if (error) { bp->b_ioflags |= BIO_ERROR; bp->b_flags |= B_INVAL; bp->b_error = error; } bp->b_dirtyoff = bp->b_dirtyend = 0; } } else { bp->b_resid = 0; bufdone(bp); return (0); } } bp->b_resid = uiop->uio_resid; bufdone(bp); return (error); } int fuse_io_flushbuf(struct vnode *vp, int waitfor, struct thread *td) { return (vn_fsync_buf(vp, waitfor)); } /* * Flush and invalidate all dirty buffers. If another process is already * doing the flush, just wait for completion. */ int fuse_io_invalbuf(struct vnode *vp, struct thread *td) { struct fuse_vnode_data *fvdat = VTOFUD(vp); int error = 0; if (VN_IS_DOOMED(vp)) return 0; ASSERT_VOP_ELOCKED(vp, "fuse_io_invalbuf"); while (fvdat->flag & FN_FLUSHINPROG) { struct proc *p = td->td_proc; if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) return EIO; fvdat->flag |= FN_FLUSHWANT; tsleep(&fvdat->flag, PRIBIO + 2, "fusevinv", 2 * hz); error = 0; if (p != NULL) { PROC_LOCK(p); if (SIGNOTEMPTY(p->p_siglist) || SIGNOTEMPTY(td->td_siglist)) error = EINTR; PROC_UNLOCK(p); } if (error == EINTR) return EINTR; } fvdat->flag |= FN_FLUSHINPROG; if (vp->v_bufobj.bo_object != NULL) { VM_OBJECT_WLOCK(vp->v_bufobj.bo_object); vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC); VM_OBJECT_WUNLOCK(vp->v_bufobj.bo_object); } error = vinvalbuf(vp, V_SAVE, PCATCH, 0); while (error) { if (error == ERESTART || error == EINTR) { fvdat->flag &= ~FN_FLUSHINPROG; if (fvdat->flag & FN_FLUSHWANT) { fvdat->flag &= ~FN_FLUSHWANT; wakeup(&fvdat->flag); } return EINTR; } error = vinvalbuf(vp, V_SAVE, PCATCH, 0); } fvdat->flag &= ~FN_FLUSHINPROG; if (fvdat->flag & FN_FLUSHWANT) { fvdat->flag &= ~FN_FLUSHWANT; wakeup(&fvdat->flag); } return (error); }