d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
4683b90591
freebsd-skq/sys/fs/fuse/fuse_io.c
Alan Somers 12292a99ac fusefs: correctly handle short writes 
If a FUSE daemon returns FOPEN_DIRECT_IO when a file is opened, then it's
allowed to write less data than was requested during a FUSE_WRITE operation
on that file handle.  fusefs should simply return a short write to userland.

The old code attempted to resend the unsent data.  Not only was that
incorrect behavior, but it did it in an ineffective way, by attempting to
"rewind" the uio and uiomove the unsent data again.

This commit correctly handles short writes by returning directly to
userland if FOPEN_DIRECT_IO was set.  If it wasn't set (making the short
write technically a protocol violation), then we resend the unsent data.
But instead of rewinding the uio, just resend the data that's already in the
kernel.

That necessitated a few changes to fuse_ipc.c to reduce the amount of bzero
activity.  fusefs may be marginally faster as a result.

PR:		236381
Sponsored by:	The FreeBSD Foundation
2019-04-04 16:51:34 +00:00

887 lines
26 KiB
C
Raw Blame History

/*-
* 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.
*
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/module.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/lock.h>
#include <sys/sx.h>
#include <sys/mutex.h>
#include <sys/rwlock.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/unistd.h>
#include <sys/filedesc.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#include "fuse.h"
#include "fuse_file.h"
#include "fuse_node.h"
#include "fuse_internal.h"
#include "fuse_ipc.h"
#include "fuse_io.h"
SDT_PROVIDER_DECLARE(fuse);
/*
* Fuse trace probe:
* arg0: verbosity. Higher numbers give more verbose messages
* arg1: Textual message
*/
SDT_PROBE_DEFINE2(fuse, , io, trace, "int", "char*");
static int
fuse_read_directbackend(struct vnode *vp, struct uio *uio,
struct ucred *cred, struct fuse_filehandle *fufh);
static int
fuse_read_biobackend(struct vnode *vp, struct uio *uio,
struct ucred *cred, struct fuse_filehandle *fufh, pid_t pid);
static int
fuse_write_directbackend(struct vnode *vp, struct uio *uio,
struct ucred *cred, struct fuse_filehandle *fufh, int ioflag);
static int
fuse_write_biobackend(struct vnode *vp, struct uio *uio,
struct ucred *cred, struct fuse_filehandle *fufh, int ioflag, pid_t pid);
SDT_PROBE_DEFINE5(fuse, , io, io_dispatch, "struct vnode*", "struct uio*",
"int", "struct ucred*", "struct fuse_filehandle*");
int
fuse_io_dispatch(struct vnode *vp, struct uio *uio, int ioflag,
struct ucred *cred, pid_t pid)
{
struct fuse_filehandle *fufh;
int err, directio;
int fflag;
MPASS(vp->v_type == VREG || vp->v_type == VDIR);
fflag = (uio->uio_rw == UIO_READ) ? FREAD : FWRITE;
err = fuse_filehandle_getrw(vp, fflag, &fufh, cred, pid);
if (err) {
printf("FUSE: io dispatch: filehandles are closed\n");
return err;
}
SDT_PROBE5(fuse, , io, io_dispatch, vp, uio, ioflag, cred, fufh);
/*
* Ideally, when the daemon asks for direct io at open time, the
* standard file flag should be set according to this, so that would
* just change the default mode, which later on could be changed via
* fcntl(2).
* But this doesn't work, the O_DIRECT flag gets cleared at some point
* (don't know where). So to make any use of the Fuse direct_io option,
* we hardwire it into the file's private data (similarly to Linux,
* btw.).
*/
directio = (ioflag & IO_DIRECT) || !fsess_opt_datacache(vnode_mount(vp));
switch (uio->uio_rw) {
case UIO_READ:
if (directio) {
SDT_PROBE2(fuse, , io, trace, 1,
"direct read of vnode");
err = fuse_read_directbackend(vp, uio, cred, fufh);
} else {
SDT_PROBE2(fuse, , io, trace, 1,
"buffered read of vnode");
err = fuse_read_biobackend(vp, uio, cred, fufh, pid);
}
break;
case UIO_WRITE:
/*
* Kludge: simulate write-through caching via write-around
* caching. Same effect, as far as never caching dirty data,
* but slightly pessimal in that newly written data is not
* cached.
*/
if (directio || fuse_data_cache_mode == FUSE_CACHE_WT) {
SDT_PROBE2(fuse, , io, trace, 1,
"direct write of vnode");
err = fuse_write_directbackend(vp, uio, cred, fufh,
ioflag);
} else {
SDT_PROBE2(fuse, , io, trace, 1,
"buffered write of vnode");
err = fuse_write_biobackend(vp, uio, cred, fufh, ioflag,
pid);
}
break;
default:
panic("uninterpreted mode passed to fuse_io_dispatch");
}
return (err);
}
SDT_PROBE_DEFINE3(fuse, , io, read_bio_backend_start, "int", "int", "int");
SDT_PROBE_DEFINE2(fuse, , io, read_bio_backend_feed, "int", "int");
SDT_PROBE_DEFINE3(fuse, , io, read_bio_backend_end, "int", "ssize_t", "int");
static int
fuse_read_biobackend(struct vnode *vp, struct uio *uio,
struct ucred *cred, struct fuse_filehandle *fufh, pid_t pid)
{
struct buf *bp;
daddr_t lbn;
int bcount;
int err = 0, n = 0, on = 0;
off_t filesize;
const int biosize = fuse_iosize(vp);
if (uio->uio_resid == 0)
return (0);
if (uio->uio_offset < 0)
return (EINVAL);
bcount = biosize;
filesize = VTOFUD(vp)->filesize;
do {
if (fuse_isdeadfs(vp)) {
err = ENXIO;
break;
}
lbn = uio->uio_offset / biosize;
on = uio->uio_offset & (biosize - 1);
SDT_PROBE3(fuse, , io, read_bio_backend_start,
biosize, (int)lbn, on);
/*
* Obtain the buffer cache block. Figure out the buffer size
* when we are at EOF. If we are modifying the size of the
* buffer based on an EOF condition we need to hold
* nfs_rslock() through obtaining the buffer to prevent
* a potential writer-appender from messing with n_size.
* Otherwise we may accidentally truncate the buffer and
* lose dirty data.
*
* Note that bcount is *not* DEV_BSIZE aligned.
*/
if ((off_t)lbn * biosize >= filesize) {
bcount = 0;
} else if ((off_t)(lbn + 1) * biosize > filesize) {
bcount = filesize - (off_t)lbn *biosize;
}
bp = getblk(vp, lbn, bcount, PCATCH, 0, 0);
if (!bp)
return (EINTR);
/*
* If B_CACHE is not set, we must issue the read. If this
* fails, we return an error.
*/
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
err = fuse_io_strategy(vp, bp);
if (err) {
brelse(bp);
return (err);
}
}
/*
* 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)
n = MIN((unsigned)(bcount - on), uio->uio_resid);
if (n > 0) {
SDT_PROBE2(fuse, , io, read_bio_backend_feed,
n, n + (int)bp->b_resid);
err = uiomove(bp->b_data + on, n, uio);
}
brelse(bp);
SDT_PROBE3(fuse, , io, read_bio_backend_end, err,
uio->uio_resid, n);
} while (err == 0 && uio->uio_resid > 0 && n > 0);
return (err);
}
SDT_PROBE_DEFINE1(fuse, , io, read_directbackend_start, "struct fuse_read_in*");
SDT_PROBE_DEFINE2(fuse, , io, read_directbackend_complete,
"struct fuse_dispatcher*", "struct uio*");
static int
fuse_read_directbackend(struct vnode *vp, struct uio *uio,
struct ucred *cred, struct fuse_filehandle *fufh)
{
struct fuse_dispatcher fdi;
struct fuse_read_in *fri;
int err = 0;
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);
SDT_PROBE1(fuse, , io, read_directbackend_start, fri);
if ((err = fdisp_wait_answ(&fdi)))
goto out;
SDT_PROBE2(fuse, , io, read_directbackend_complete,
fdi.iosize, uio);
if ((err = uiomove(fdi.answ, MIN(fri->size, fdi.iosize), uio)))
break;
if (fdi.iosize < fri->size)
break;
}
out:
fdisp_destroy(&fdi);
return (err);
}
static int
fuse_write_directbackend(struct vnode *vp, struct uio *uio,
struct ucred *cred, struct fuse_filehandle *fufh, int ioflag)
{
struct fuse_vnode_data *fvdat = VTOFUD(vp);
struct fuse_write_in *fwi;
struct fuse_write_out *fwo;
struct fuse_dispatcher fdi;
size_t chunksize;
void *fwi_data;
off_t as_written_offset;
int diff;
int err = 0;
bool direct_io = fufh->fuse_open_flags & FOPEN_DIRECT_IO;
if (uio->uio_resid == 0)
return (0);
if (ioflag & IO_APPEND)
uio_setoffset(uio, fvdat->filesize);
fdisp_init(&fdi, 0);
while (uio->uio_resid > 0) {
chunksize = MIN(uio->uio_resid,
fuse_get_mpdata(vp->v_mount)->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_data = (char *)fdi.indata + sizeof(*fwi);
if ((err = uiomove(fwi_data, chunksize, uio)))
break;
retry:
if ((err = fdisp_wait_answ(&fdi)))
break;
fwo = ((struct fuse_write_out *)fdi.answ);
/* 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 > fvdat->filesize &&
fuse_data_cache_mode != FUSE_CACHE_UC) {
fuse_vnode_setsize(vp, cred, as_written_offset);
fvdat->flag &= ~FN_SIZECHANGE;
}
if (diff < 0) {
printf("WARNING: misbehaving FUSE filesystem "
"wrote more data than we provided it\n");
err = EINVAL;
break;
} else if (diff > 0) {
/* Short write */
if (!direct_io) {
printf("WARNING: misbehaving FUSE filesystem: "
"short writes are only allowed with "
"direct_io\n");
}
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;
goto retry;
}
}
}
fdisp_destroy(&fdi);
return (err);
}
SDT_PROBE_DEFINE6(fuse, , io, write_biobackend_start, "int64_t", "int", "int",
"struct uio*", "int", "bool");
SDT_PROBE_DEFINE2(fuse, , io, write_biobackend_append_race, "long", "int");
static 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;
int bcount;
int n, on, err = 0;
const int biosize = fuse_iosize(vp);
KASSERT(uio->uio_rw == UIO_WRITE, ("ncl_write mode"));
if (vp->v_type != VREG)
return (EIO);
if (uio->uio_offset < 0)
return (EINVAL);
if (uio->uio_resid == 0)
return (0);
if (ioflag & IO_APPEND)
uio_setoffset(uio, fvdat->filesize);
/*
* Find all of this file's B_NEEDCOMMIT buffers. If our writes
* would exceed the local maximum per-file write commit size when
* combined with those, we must decide whether to flush,
* go synchronous, or return err. We don't bother checking
* IO_UNIT -- we just make all writes atomic anyway, as there's
* no point optimizing for something that really won't ever happen.
*/
do {
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:
/*
* Handle direct append and file extension cases, calculate
* unaligned buffer size.
*/
if (uio->uio_offset == fvdat->filesize && n) {
/*
* Get the buffer (in its pre-append state to maintain
* B_CACHE if it was previously set). Resize the
* nfsnode after we have locked the buffer to prevent
* readers from reading garbage.
*/
bcount = on;
SDT_PROBE6(fuse, , io, write_biobackend_start,
lbn, on, n, uio, bcount, true);
bp = getblk(vp, lbn, bcount, PCATCH, 0, 0);
if (bp != NULL) {
long save;
err = fuse_vnode_setsize(vp, cred,
uio->uio_offset + n);
if (err) {
brelse(bp);
break;
}
save = bp->b_flags & B_CACHE;
bcount += n;
allocbuf(bp, bcount);
bp->b_flags |= save;
}
} else {
/*
* Obtain the locked cache block first, and then
* adjust the file's size as appropriate.
*/
bcount = on + n;
if ((off_t)lbn * biosize + bcount < fvdat->filesize) {
if ((off_t)(lbn + 1) * biosize < fvdat->filesize)
bcount = biosize;
else
bcount = fvdat->filesize -
(off_t)lbn *biosize;
}
SDT_PROBE6(fuse, , io, write_biobackend_start,
lbn, on, n, uio, bcount, false);
bp = getblk(vp, lbn, bcount, PCATCH, 0, 0);
if (bp && uio->uio_offset + n > fvdat->filesize) {
err = fuse_vnode_setsize(vp, cred,
uio->uio_offset + n);
if (err) {
brelse(bp);
break;
}
}
}
if (!bp) {
err = EINTR;
break;
}
/*
* 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_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(fuse, , 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.)
*/
bwrite(bp);
if (bp->b_error == EINTR) {
err = EINTR;
break;
}
goto again;
}
err = uiomove((char *)bp->b_data + on, n, uio);
/*
* Since this block is being modified, it must be written
* again and not just committed. Since write clustering does
* not work for the stage 1 data write, only the stage 2
* commit rpc, we have to clear B_CLUSTEROK as well.
*/
bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
if (err) {
bp->b_ioflags |= BIO_ERROR;
bp->b_error = err;
brelse(bp);
break;
}
/*
* 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);
}
err = bwrite(bp);
if (err)
break;
} while (uio->uio_resid > 0 && n > 0);
if (fuse_sync_resize && (fvdat->flag & FN_SIZECHANGE) != 0)
fuse_vnode_savesize(vp, cred, pid);
return (err);
}
int
fuse_io_strategy(struct vnode *vp, struct buf *bp)
{
struct fuse_filehandle *fufh;
struct fuse_vnode_data *fvdat = VTOFUD(vp);
struct ucred *cred;
struct uio *uiop;
struct uio uio;
struct iovec io;
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.
*
* TODO: eliminate this hacky check once the FUFH table is gone
*/
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) {
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_blkno) * biosize;
error = fuse_read_directbackend(vp, uiop, cred, fufh);
/* XXXCEM: Potentially invalid access to cached_attrs here */
if ((!error && uiop->uio_resid) ||
(fsess_opt_brokenio(vnode_mount(vp)) && error == EIO &&
uiop->uio_offset < fvdat->filesize && fvdat->filesize > 0 &&
uiop->uio_offset >= fvdat->cached_attrs.va_size)) {
/*
* If we had a short read with no error, we must have
* hit a file hole. We should zero-fill the remainder.
* This can also occur if the server hits the file EOF.
*
* Holes used to be able to occur due to pending
* writes, but that is not possible any longer.
*/
int nread = bp->b_bcount - uiop->uio_resid;
int left = uiop->uio_resid;
if (error != 0) {
printf("FUSE: Fix broken io: offset %ju, "
" resid %zd, file size %ju/%ju\n",
(uintmax_t)uiop->uio_offset,
uiop->uio_resid, fvdat->filesize,
fvdat->cached_attrs.va_size);
error = 0;
}
if (left > 0)
bzero((char *)bp->b_data + nread, left);
uiop->uio_resid = 0;
}
if (error) {
bp->b_ioflags |= BIO_ERROR;
bp->b_error = error;
}
} else {
/*
* If we only need to commit, try to commit
*/
if (bp->b_flags & B_NEEDCOMMIT) {
SDT_PROBE2(fuse, , io, trace, 1,
"write: B_NEEDCOMMIT flags set");
}
/*
* Setup for actual write
*/
if ((off_t)bp->b_blkno * biosize + bp->b_dirtyend >
fvdat->filesize)
bp->b_dirtyend = fvdat->filesize -
(off_t)bp->b_blkno * 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_blkno * biosize
+ bp->b_dirtyoff;
io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
uiop->uio_rw = UIO_WRITE;
error = fuse_write_directbackend(vp, uiop, cred, fufh, 0);
if (error == EINTR || error == ETIMEDOUT
|| (!error && (bp->b_flags & B_NEEDCOMMIT))) {
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)
{
struct vop_fsync_args a = {
.a_vp = vp,
.a_waitfor = waitfor,
.a_td = td,
};
return (vop_stdfsync(&a));
}
/*
* 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 (vp->v_iflag & VI_DOOMED)
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);
}
Reference in New Issue View Git Blame Copy Permalink