1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2007-2009 Google Inc. and Amit Singh
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/systm.h>
68#include <sys/counter.h>
69#include <sys/module.h>
70#include <sys/errno.h>
71#include <sys/param.h>
72#include <sys/kernel.h>
73#include <sys/conf.h>
74#include <sys/uio.h>
75#include <sys/malloc.h>
76#include <sys/queue.h>
77#include <sys/lock.h>
78#include <sys/sx.h>
79#include <sys/mutex.h>
80#include <sys/proc.h>
81#include <sys/vnode.h>
82#include <sys/namei.h>
83#include <sys/mount.h>
84#include <sys/sysctl.h>
85#include <sys/fcntl.h>
86#include <sys/priv.h>
87#include <sys/buf.h>
88#include <security/mac/mac_framework.h>
89#include <vm/vm.h>
90#include <vm/vm_extern.h>
91
92#include "fuse.h"
93#include "fuse_node.h"
94#include "fuse_internal.h"
95#include "fuse_io.h"
96#include "fuse_ipc.h"
97
98SDT_PROVIDER_DECLARE(fusefs);
99/*
100 * Fuse trace probe:
101 * arg0: verbosity.  Higher numbers give more verbose messages
102 * arg1: Textual message
103 */
104SDT_PROBE_DEFINE2(fusefs, , node, trace, "int", "char*");
105
106MALLOC_DEFINE(M_FUSEVN, "fuse_vnode", "fuse vnode private data");
107
108static int sysctl_fuse_cache_mode(SYSCTL_HANDLER_ARGS);
109
110static counter_u64_t fuse_node_count;
111
112SYSCTL_COUNTER_U64(_vfs_fusefs_stats, OID_AUTO, node_count, CTLFLAG_RD,
113    &fuse_node_count, "Count of FUSE vnodes");
114
115int	fuse_data_cache_mode = FUSE_CACHE_WT;
116
117/*
118 * DEPRECATED
119 * This sysctl is no longer needed as of fuse protocol 7.23.  Individual
120 * servers can select the cache behavior they need for each mountpoint:
121 * - writethrough: the default
122 * - writeback: set FUSE_WRITEBACK_CACHE in fuse_init_out.flags
123 * - uncached: set FOPEN_DIRECT_IO for every file
124 * The sysctl is retained primarily for use by jails supporting older FUSE
125 * protocols.  It may be removed entirely once FreeBSD 11.3 and 12.0 are EOL.
126 */
127SYSCTL_PROC(_vfs_fusefs, OID_AUTO, data_cache_mode, CTLTYPE_INT|CTLFLAG_RW,
128    &fuse_data_cache_mode, 0, sysctl_fuse_cache_mode, "I",
129    "Zero: disable caching of FUSE file data; One: write-through caching "
130    "(default); Two: write-back caching (generally unsafe)");
131
132static int
133sysctl_fuse_cache_mode(SYSCTL_HANDLER_ARGS)
134{
135	int val, error;
136
137	val = *(int *)arg1;
138	error = sysctl_handle_int(oidp, &val, 0, req);
139	if (error || !req->newptr)
140		return (error);
141
142	switch (val) {
143	case FUSE_CACHE_UC:
144	case FUSE_CACHE_WT:
145	case FUSE_CACHE_WB:
146		*(int *)arg1 = val;
147		break;
148	default:
149		return (EDOM);
150	}
151	return (0);
152}
153
154static void
155fuse_vnode_init(struct vnode *vp, struct fuse_vnode_data *fvdat,
156    uint64_t nodeid, enum vtype vtyp)
157{
158	fvdat->nid = nodeid;
159	LIST_INIT(&fvdat->handles);
160	vattr_null(&fvdat->cached_attrs);
161	if (nodeid == FUSE_ROOT_ID) {
162		vp->v_vflag |= VV_ROOT;
163	}
164	vp->v_type = vtyp;
165	vp->v_data = fvdat;
166
167	counter_u64_add(fuse_node_count, 1);
168}
169
170void
171fuse_vnode_destroy(struct vnode *vp)
172{
173	struct fuse_vnode_data *fvdat = vp->v_data;
174
175	vp->v_data = NULL;
176	KASSERT(LIST_EMPTY(&fvdat->handles),
177		("Destroying fuse vnode with open files!"));
178	free(fvdat, M_FUSEVN);
179
180	counter_u64_add(fuse_node_count, -1);
181}
182
183int
184fuse_vnode_cmp(struct vnode *vp, void *nidp)
185{
186	return (VTOI(vp) != *((uint64_t *)nidp));
187}
188
189SDT_PROBE_DEFINE3(fusefs, , node, stale_vnode, "struct vnode*", "enum vtype",
190		"uint64_t");
191static int
192fuse_vnode_alloc(struct mount *mp,
193    struct thread *td,
194    uint64_t nodeid,
195    enum vtype vtyp,
196    struct vnode **vpp)
197{
198	struct fuse_data *data;
199	struct fuse_vnode_data *fvdat;
200	struct vnode *vp2;
201	int err = 0;
202
203	data = fuse_get_mpdata(mp);
204	if (vtyp == VNON) {
205		return EINVAL;
206	}
207	*vpp = NULL;
208	err = vfs_hash_get(mp, fuse_vnode_hash(nodeid), LK_EXCLUSIVE, td, vpp,
209	    fuse_vnode_cmp, &nodeid);
210	if (err)
211		return (err);
212
213	if (*vpp) {
214		if ((*vpp)->v_type != vtyp) {
215			/*
216			 * STALE vnode!  This probably indicates a buggy
217			 * server, but it could also be the result of a race
218			 * between FUSE_LOOKUP and another client's
219			 * FUSE_UNLINK/FUSE_CREATE
220			 */
221			SDT_PROBE3(fusefs, , node, stale_vnode, *vpp, vtyp,
222				nodeid);
223			fuse_internal_vnode_disappear(*vpp);
224			lockmgr((*vpp)->v_vnlock, LK_RELEASE, NULL);
225			*vpp = NULL;
226			return (EAGAIN);
227		}
228		MPASS((*vpp)->v_data != NULL);
229		MPASS(VTOFUD(*vpp)->nid == nodeid);
230		SDT_PROBE2(fusefs, , node, trace, 1, "vnode taken from hash");
231		return (0);
232	}
233	fvdat = malloc(sizeof(*fvdat), M_FUSEVN, M_WAITOK | M_ZERO);
234	switch (vtyp) {
235	case VFIFO:
236		err = getnewvnode("fuse", mp, &fuse_fifoops, vpp);
237		break;
238	default:
239		err = getnewvnode("fuse", mp, &fuse_vnops, vpp);
240		break;
241	}
242	if (err) {
243		free(fvdat, M_FUSEVN);
244		return (err);
245	}
246	lockmgr((*vpp)->v_vnlock, LK_EXCLUSIVE, NULL);
247	fuse_vnode_init(*vpp, fvdat, nodeid, vtyp);
248	err = insmntque(*vpp, mp);
249	ASSERT_VOP_ELOCKED(*vpp, "fuse_vnode_alloc");
250	if (err) {
251		lockmgr((*vpp)->v_vnlock, LK_RELEASE, NULL);
252		free(fvdat, M_FUSEVN);
253		*vpp = NULL;
254		return (err);
255	}
256	/* Disallow async reads for fifos because UFS does.  I don't know why */
257	if (data->dataflags & FSESS_ASYNC_READ && vtyp != VFIFO)
258		VN_LOCK_ASHARE(*vpp);
259
260	err = vfs_hash_insert(*vpp, fuse_vnode_hash(nodeid), LK_EXCLUSIVE,
261	    td, &vp2, fuse_vnode_cmp, &nodeid);
262	if (err) {
263		lockmgr((*vpp)->v_vnlock, LK_RELEASE, NULL);
264		free(fvdat, M_FUSEVN);
265		*vpp = NULL;
266		return (err);
267	}
268	if (vp2 != NULL) {
269		*vpp = vp2;
270		return (0);
271	}
272
273	ASSERT_VOP_ELOCKED(*vpp, "fuse_vnode_alloc");
274
275	return (0);
276}
277
278int
279fuse_vnode_get(struct mount *mp,
280    struct fuse_entry_out *feo,
281    uint64_t nodeid,
282    struct vnode *dvp,
283    struct vnode **vpp,
284    struct componentname *cnp,
285    enum vtype vtyp)
286{
287	struct thread *td = (cnp != NULL ? cnp->cn_thread : curthread);
288	/*
289	 * feo should only be NULL for the root directory, which (when libfuse
290	 * is used) always has generation 0
291	 */
292	uint64_t generation = feo ? feo->generation : 0;
293	int err = 0;
294
295	err = fuse_vnode_alloc(mp, td, nodeid, vtyp, vpp);
296	if (err) {
297		return err;
298	}
299	if (dvp != NULL) {
300		MPASS(cnp && (cnp->cn_flags & ISDOTDOT) == 0);
301		MPASS(cnp &&
302			!(cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.'));
303		fuse_vnode_setparent(*vpp, dvp);
304	}
305	if (dvp != NULL && cnp != NULL && (cnp->cn_flags & MAKEENTRY) != 0 &&
306	    feo != NULL &&
307	    (feo->entry_valid != 0 || feo->entry_valid_nsec != 0)) {
308		struct timespec timeout;
309
310		ASSERT_VOP_LOCKED(*vpp, "fuse_vnode_get");
311		ASSERT_VOP_LOCKED(dvp, "fuse_vnode_get");
312
313		fuse_validity_2_timespec(feo, &timeout);
314		cache_enter_time(dvp, *vpp, cnp, &timeout, NULL);
315	}
316
317	VTOFUD(*vpp)->generation = generation;
318	/*
319	 * In userland, libfuse uses cached lookups for dot and dotdot entries,
320	 * thus it does not really bump the nlookup counter for forget.
321	 * Follow the same semantic and avoid the bump in order to keep
322	 * nlookup counters consistent.
323	 */
324	if (cnp == NULL || ((cnp->cn_flags & ISDOTDOT) == 0 &&
325	    (cnp->cn_namelen != 1 || cnp->cn_nameptr[0] != '.')))
326		VTOFUD(*vpp)->nlookup++;
327
328	return 0;
329}
330
331/*
332 * Called for every fusefs vnode open to initialize the vnode (not
333 * fuse_filehandle) for use
334 */
335void
336fuse_vnode_open(struct vnode *vp, int32_t fuse_open_flags, struct thread *td)
337{
338	if (vnode_vtype(vp) == VREG)
339		vnode_create_vobject(vp, 0, td);
340}
341
342int
343fuse_vnode_savesize(struct vnode *vp, struct ucred *cred, pid_t pid)
344{
345	struct fuse_vnode_data *fvdat = VTOFUD(vp);
346	struct thread *td = curthread;
347	struct fuse_filehandle *fufh = NULL;
348	struct fuse_dispatcher fdi;
349	struct fuse_setattr_in *fsai;
350	int err = 0;
351
352	ASSERT_VOP_ELOCKED(vp, "fuse_io_extend");
353
354	if (fuse_isdeadfs(vp)) {
355		return EBADF;
356	}
357	if (vnode_vtype(vp) == VDIR) {
358		return EISDIR;
359	}
360	if (vfs_isrdonly(vnode_mount(vp))) {
361		return EROFS;
362	}
363	if (cred == NULL) {
364		cred = td->td_ucred;
365	}
366	fdisp_init(&fdi, sizeof(*fsai));
367	fdisp_make_vp(&fdi, FUSE_SETATTR, vp, td, cred);
368	fsai = fdi.indata;
369	fsai->valid = 0;
370
371	/* Truncate to a new value. */
372	MPASS((fvdat->flag & FN_SIZECHANGE) != 0);
373	fsai->size = fvdat->cached_attrs.va_size;
374	fsai->valid |= FATTR_SIZE;
375
376	fuse_filehandle_getrw(vp, FWRITE, &fufh, cred, pid);
377	if (fufh) {
378		fsai->fh = fufh->fh_id;
379		fsai->valid |= FATTR_FH;
380	}
381	err = fdisp_wait_answ(&fdi);
382	fdisp_destroy(&fdi);
383	if (err == 0)
384		fvdat->flag &= ~FN_SIZECHANGE;
385
386	return err;
387}
388
389/*
390 * Adjust the vnode's size to a new value, such as that provided by
391 * FUSE_GETATTR.
392 */
393int
394fuse_vnode_setsize(struct vnode *vp, off_t newsize)
395{
396	struct fuse_vnode_data *fvdat = VTOFUD(vp);
397	struct vattr *attrs;
398	off_t oldsize;
399	size_t iosize;
400	struct buf *bp = NULL;
401	int err = 0;
402
403	ASSERT_VOP_ELOCKED(vp, "fuse_vnode_setsize");
404
405	iosize = fuse_iosize(vp);
406	oldsize = fvdat->cached_attrs.va_size;
407	fvdat->cached_attrs.va_size = newsize;
408	if ((attrs = VTOVA(vp)) != NULL)
409		attrs->va_size = newsize;
410
411	if (newsize < oldsize) {
412		daddr_t lbn;
413
414		err = vtruncbuf(vp, newsize, fuse_iosize(vp));
415		if (err)
416			goto out;
417		if (newsize % iosize == 0)
418			goto out;
419		/*
420		 * Zero the contents of the last partial block.
421		 * Sure seems like vtruncbuf should do this for us.
422		 */
423
424		lbn = newsize / iosize;
425		bp = getblk(vp, lbn, iosize, PCATCH, 0, 0);
426		if (!bp) {
427			err = EINTR;
428			goto out;
429		}
430		if (!(bp->b_flags & B_CACHE))
431			goto out;	/* Nothing to do */
432		MPASS(bp->b_flags & B_VMIO);
433		vfs_bio_clrbuf(bp);
434		bp->b_dirtyend = MIN(bp->b_dirtyend, newsize - lbn * iosize);
435	}
436out:
437	if (bp)
438		brelse(bp);
439	vnode_pager_setsize(vp, newsize);
440	return err;
441}
442
443/* Get the current, possibly dirty, size of the file */
444int
445fuse_vnode_size(struct vnode *vp, off_t *filesize, struct ucred *cred,
446	struct thread *td)
447{
448	struct fuse_vnode_data *fvdat = VTOFUD(vp);
449	int error = 0;
450
451	if (!(fvdat->flag & FN_SIZECHANGE) &&
452		(!fuse_vnode_attr_cache_valid(vp) ||
453		  fvdat->cached_attrs.va_size == VNOVAL))
454		error = fuse_internal_do_getattr(vp, NULL, cred, td);
455
456	if (!error)
457		*filesize = fvdat->cached_attrs.va_size;
458
459	return error;
460}
461
462void
463fuse_vnode_undirty_cached_timestamps(struct vnode *vp)
464{
465	struct fuse_vnode_data *fvdat = VTOFUD(vp);
466
467	fvdat->flag &= ~(FN_MTIMECHANGE | FN_CTIMECHANGE);
468}
469
470/* Update a fuse file's cached timestamps */
471void
472fuse_vnode_update(struct vnode *vp, int flags)
473{
474	struct fuse_vnode_data *fvdat = VTOFUD(vp);
475	struct fuse_data *data = fuse_get_mpdata(vnode_mount(vp));
476	struct timespec ts;
477
478	vfs_timestamp(&ts);
479
480	if (data->time_gran > 1)
481		ts.tv_nsec = rounddown(ts.tv_nsec, data->time_gran);
482
483	if (flags & FN_MTIMECHANGE)
484		fvdat->cached_attrs.va_mtime = ts;
485	if (flags & FN_CTIMECHANGE)
486		fvdat->cached_attrs.va_ctime = ts;
487
488	fvdat->flag |= flags;
489}
490
491void
492fuse_node_init(void)
493{
494	fuse_node_count = counter_u64_alloc(M_WAITOK);
495}
496
497void
498fuse_node_destroy(void)
499{
500	counter_u64_free(fuse_node_count);
501}
502