xref: /freebsd/sys/fs/tarfs/tarfs_io.c (revision 91e03758ded5dbaf7a5a6247c3eb61a07c95494d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2013 Juniper Networks, Inc.
5  * Copyright (c) 2022-2023 Klara, Inc.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include "opt_tarfs.h"
30 #include "opt_zstdio.h"
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/counter.h>
35 #include <sys/bio.h>
36 #include <sys/buf.h>
37 #include <sys/malloc.h>
38 #include <sys/mount.h>
39 #include <sys/sysctl.h>
40 #include <sys/uio.h>
41 #include <sys/vnode.h>
42 
43 #if defined(ZSTDIO)
44 #define TARFS_ZIO 1
45 #else
46 #undef TARFS_ZIO
47 #endif
48 
49 #ifdef ZSTDIO
50 #define ZSTD_STATIC_LINKING_ONLY
51 #include <contrib/zstd/lib/zstd.h>
52 #endif
53 
54 #include <fs/tarfs/tarfs.h>
55 #include <fs/tarfs/tarfs_dbg.h>
56 
57 #ifdef TARFS_DEBUG
58 SYSCTL_NODE(_vfs_tarfs, OID_AUTO, zio, CTLFLAG_RD, 0,
59     "Tar filesystem decompression layer");
60 COUNTER_U64_DEFINE_EARLY(tarfs_zio_inflated);
61 SYSCTL_COUNTER_U64(_vfs_tarfs_zio, OID_AUTO, inflated, CTLFLAG_RD,
62     &tarfs_zio_inflated, "Amount of compressed data inflated.");
63 COUNTER_U64_DEFINE_EARLY(tarfs_zio_consumed);
64 SYSCTL_COUNTER_U64(_vfs_tarfs_zio, OID_AUTO, consumed, CTLFLAG_RD,
65     &tarfs_zio_consumed, "Amount of compressed data consumed.");
66 COUNTER_U64_DEFINE_EARLY(tarfs_zio_bounced);
67 SYSCTL_COUNTER_U64(_vfs_tarfs_zio, OID_AUTO, bounced, CTLFLAG_RD,
68     &tarfs_zio_bounced, "Amount of decompressed data bounced.");
69 
70 static int
tarfs_sysctl_handle_zio_reset(SYSCTL_HANDLER_ARGS)71 tarfs_sysctl_handle_zio_reset(SYSCTL_HANDLER_ARGS)
72 {
73 	unsigned int tmp;
74 	int error;
75 
76 	tmp = 0;
77 	if ((error = SYSCTL_OUT(req, &tmp, sizeof(tmp))) != 0)
78 		return (error);
79 	if (req->newptr != NULL) {
80 		if ((error = SYSCTL_IN(req, &tmp, sizeof(tmp))) != 0)
81 			return (error);
82 		counter_u64_zero(tarfs_zio_inflated);
83 		counter_u64_zero(tarfs_zio_consumed);
84 		counter_u64_zero(tarfs_zio_bounced);
85 	}
86 	return (0);
87 }
88 
89 SYSCTL_PROC(_vfs_tarfs_zio, OID_AUTO, reset,
90     CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW,
91     NULL, 0, tarfs_sysctl_handle_zio_reset, "IU",
92     "Reset compression counters.");
93 #endif
94 
95 MALLOC_DEFINE(M_TARFSZSTATE, "tarfs zstate", "tarfs decompression state");
96 MALLOC_DEFINE(M_TARFSZBUF, "tarfs zbuf", "tarfs decompression buffers");
97 
98 #define XZ_MAGIC		(uint8_t[]){ 0xfd, 0x37, 0x7a, 0x58, 0x5a }
99 #define ZLIB_MAGIC		(uint8_t[]){ 0x1f, 0x8b, 0x08 }
100 #define ZSTD_MAGIC		(uint8_t[]){ 0x28, 0xb5, 0x2f, 0xfd }
101 
102 #ifdef ZSTDIO
103 struct tarfs_zstd {
104 	ZSTD_DStream *zds;
105 };
106 #endif
107 
108 /* XXX review use of curthread / uio_td / td_cred */
109 
110 /*
111  * Reads from the tar file according to the provided uio.  If the archive
112  * is compressed and raw is false, reads the decompressed stream;
113  * otherwise, reads directly from the original file.  Returns 0 on success
114  * and a positive errno value on failure.
115  */
116 int
tarfs_io_read(struct tarfs_mount * tmp,bool raw,struct uio * uiop)117 tarfs_io_read(struct tarfs_mount *tmp, bool raw, struct uio *uiop)
118 {
119 	void *rl = NULL;
120 	off_t off = uiop->uio_offset;
121 	size_t len = uiop->uio_resid;
122 	int error;
123 
124 	if (raw || tmp->znode == NULL) {
125 		rl = vn_rangelock_rlock(tmp->vp, off, off + len);
126 		error = vn_lock(tmp->vp, LK_SHARED);
127 		if (error == 0) {
128 			error = VOP_READ(tmp->vp, uiop, IO_NODELOCKED,
129 			    uiop->uio_td->td_ucred);
130 			VOP_UNLOCK(tmp->vp);
131 		}
132 		vn_rangelock_unlock(tmp->vp, rl);
133 	} else {
134 		error = vn_lock(tmp->znode, LK_EXCLUSIVE);
135 		if (error == 0) {
136 			error = VOP_READ(tmp->znode, uiop,
137 			    IO_DIRECT | IO_NODELOCKED,
138 			    uiop->uio_td->td_ucred);
139 			VOP_UNLOCK(tmp->znode);
140 		}
141 	}
142 	TARFS_DPF(IO, "%s(%zu, %zu) = %d (resid %zd)\n", __func__,
143 	    (size_t)off, len, error, uiop->uio_resid);
144 	return (error);
145 }
146 
147 /*
148  * Reads from the tar file into the provided buffer.  If the archive is
149  * compressed and raw is false, reads the decompressed stream; otherwise,
150  * reads directly from the original file.  Returns the number of bytes
151  * read on success, 0 on EOF, and a negative errno value on failure.
152  */
153 ssize_t
tarfs_io_read_buf(struct tarfs_mount * tmp,bool raw,void * buf,off_t off,size_t len)154 tarfs_io_read_buf(struct tarfs_mount *tmp, bool raw,
155     void *buf, off_t off, size_t len)
156 {
157 	struct uio auio;
158 	struct iovec aiov;
159 	ssize_t res;
160 	int error;
161 
162 	if (len == 0) {
163 		TARFS_DPF(IO, "%s(%zu, %zu) null\n", __func__,
164 		    (size_t)off, len);
165 		return (0);
166 	}
167 	aiov.iov_base = buf;
168 	aiov.iov_len = len;
169 	auio.uio_iov = &aiov;
170 	auio.uio_iovcnt = 1;
171 	auio.uio_offset = off;
172 	auio.uio_segflg = UIO_SYSSPACE;
173 	auio.uio_rw = UIO_READ;
174 	auio.uio_resid = len;
175 	auio.uio_td = curthread;
176 	error = tarfs_io_read(tmp, raw, &auio);
177 	if (error != 0) {
178 		TARFS_DPF(IO, "%s(%zu, %zu) error %d\n", __func__,
179 		    (size_t)off, len, error);
180 		return (-error);
181 	}
182 	res = len - auio.uio_resid;
183 	if (res == 0 && len != 0) {
184 		TARFS_DPF(IO, "%s(%zu, %zu) eof\n", __func__,
185 		    (size_t)off, len);
186 	} else {
187 		TARFS_DPF(IO, "%s(%zu, %zu) read %zd | %*D\n", __func__,
188 		    (size_t)off, len, res,
189 		    (int)(res > 8 ? 8 : res), (uint8_t *)buf, " ");
190 	}
191 	return (res);
192 }
193 
194 #ifdef ZSTDIO
195 static void *
tarfs_zstate_alloc(void * opaque,size_t size)196 tarfs_zstate_alloc(void *opaque, size_t size)
197 {
198 
199 	(void)opaque;
200 	return (malloc(size, M_TARFSZSTATE, M_WAITOK));
201 }
202 #endif
203 
204 #ifdef ZSTDIO
205 static void
tarfs_zstate_free(void * opaque,void * address)206 tarfs_zstate_free(void *opaque, void *address)
207 {
208 
209 	(void)opaque;
210 	free(address, M_TARFSZSTATE);
211 }
212 #endif
213 
214 #ifdef ZSTDIO
215 static ZSTD_customMem tarfs_zstd_mem = {
216 	tarfs_zstate_alloc,
217 	tarfs_zstate_free,
218 	NULL,
219 };
220 #endif
221 
222 #ifdef TARFS_ZIO
223 /*
224  * Updates the decompression frame index, recording the current input and
225  * output offsets in a new index entry, and growing the index if
226  * necessary.
227  */
228 static void
tarfs_zio_update_index(struct tarfs_zio * zio,off_t i,off_t o)229 tarfs_zio_update_index(struct tarfs_zio *zio, off_t i, off_t o)
230 {
231 
232 	if (++zio->curidx >= zio->nidx) {
233 		if (++zio->nidx > zio->szidx) {
234 			zio->szidx *= 2;
235 			zio->idx = realloc(zio->idx,
236 			    zio->szidx * sizeof(*zio->idx),
237 			    M_TARFSZSTATE, M_ZERO | M_WAITOK);
238 			TARFS_DPF(ALLOC, "%s: resized zio index\n", __func__);
239 		}
240 		zio->idx[zio->curidx].i = i;
241 		zio->idx[zio->curidx].o = o;
242 		TARFS_DPF(ZIDX, "%s: index %u = i %zu o %zu\n", __func__,
243 		    zio->curidx, (size_t)zio->idx[zio->curidx].i,
244 		    (size_t)zio->idx[zio->curidx].o);
245 	}
246 	MPASS(zio->idx[zio->curidx].i == i);
247 	MPASS(zio->idx[zio->curidx].o == o);
248 }
249 #endif
250 
251 /*
252  * VOP_ACCESS for zio node.
253  */
254 static int
tarfs_zaccess(struct vop_access_args * ap)255 tarfs_zaccess(struct vop_access_args *ap)
256 {
257 	struct vnode *vp = ap->a_vp;
258 	struct tarfs_zio *zio = vp->v_data;
259 	struct tarfs_mount *tmp = zio->tmp;
260 	accmode_t accmode = ap->a_accmode;
261 	int error = EPERM;
262 
263 	if (accmode == VREAD) {
264 		error = vn_lock(tmp->vp, LK_SHARED);
265 		if (error == 0) {
266 			error = VOP_ACCESS(tmp->vp, accmode, ap->a_cred, ap->a_td);
267 			VOP_UNLOCK(tmp->vp);
268 		}
269 	}
270 	TARFS_DPF(ZIO, "%s(%d) = %d\n", __func__, accmode, error);
271 	return (error);
272 }
273 
274 /*
275  * VOP_GETATTR for zio node.
276  */
277 static int
tarfs_zgetattr(struct vop_getattr_args * ap)278 tarfs_zgetattr(struct vop_getattr_args *ap)
279 {
280 	struct vattr va;
281 	struct vnode *vp = ap->a_vp;
282 	struct tarfs_zio *zio = vp->v_data;
283 	struct tarfs_mount *tmp = zio->tmp;
284 	struct vattr *vap = ap->a_vap;
285 	int error = 0;
286 
287 	VATTR_NULL(vap);
288 	error = vn_lock(tmp->vp, LK_SHARED);
289 	if (error == 0) {
290 		error = VOP_GETATTR(tmp->vp, &va, ap->a_cred);
291 		VOP_UNLOCK(tmp->vp);
292 		if (error == 0) {
293 			vap->va_type = VREG;
294 			vap->va_mode = va.va_mode;
295 			vap->va_nlink = 1;
296 			vap->va_gid = va.va_gid;
297 			vap->va_uid = va.va_uid;
298 			vap->va_fsid = vp->v_mount->mnt_stat.f_fsid.val[0];
299 			vap->va_fileid = TARFS_ZIOINO;
300 			vap->va_size = zio->idx[zio->nidx - 1].o;
301 			vap->va_blocksize = vp->v_mount->mnt_stat.f_iosize;
302 			vap->va_atime = va.va_atime;
303 			vap->va_ctime = va.va_ctime;
304 			vap->va_mtime = va.va_mtime;
305 			vap->va_birthtime = tmp->root->birthtime;
306 			vap->va_bytes = va.va_bytes;
307 		}
308 	}
309 	TARFS_DPF(ZIO, "%s() = %d\n", __func__, error);
310 	return (error);
311 }
312 
313 #ifdef ZSTDIO
314 /*
315  * VOP_READ for zio node, zstd edition.
316  */
317 static int
tarfs_zread_zstd(struct tarfs_zio * zio,struct uio * uiop)318 tarfs_zread_zstd(struct tarfs_zio *zio, struct uio *uiop)
319 {
320 	void *ibuf = NULL, *obuf = NULL, *rl = NULL;
321 	struct uio auio;
322 	struct iovec aiov;
323 	struct tarfs_mount *tmp = zio->tmp;
324 	struct tarfs_zstd *zstd = zio->zstd;
325 	struct thread *td = curthread;
326 	ZSTD_inBuffer zib;
327 	ZSTD_outBuffer zob;
328 	off_t zsize;
329 	off_t ipos, opos;
330 	size_t ilen, olen;
331 	size_t zerror;
332 	off_t off = uiop->uio_offset;
333 	size_t len = uiop->uio_resid;
334 	size_t resid = uiop->uio_resid;
335 	size_t bsize;
336 	int error;
337 	bool reset = false;
338 
339 	/* do we have to rewind? */
340 	if (off < zio->opos) {
341 		while (zio->curidx > 0 && off < zio->idx[zio->curidx].o)
342 			zio->curidx--;
343 		reset = true;
344 	}
345 	/* advance to the nearest index entry */
346 	if (off > zio->opos) {
347 		// XXX maybe do a binary search instead
348 		while (zio->curidx < zio->nidx - 1 &&
349 		    off >= zio->idx[zio->curidx + 1].o) {
350 			zio->curidx++;
351 			reset = true;
352 		}
353 	}
354 	/* reset the decompression stream if needed */
355 	if (reset) {
356 		zio->ipos = zio->idx[zio->curidx].i;
357 		zio->opos = zio->idx[zio->curidx].o;
358 		ZSTD_resetDStream(zstd->zds);
359 		TARFS_DPF(ZIDX, "%s: skipping to index %u = i %zu o %zu\n", __func__,
360 		    zio->curidx, (size_t)zio->ipos, (size_t)zio->opos);
361 	} else {
362 		TARFS_DPF(ZIDX, "%s: continuing at i %zu o %zu\n", __func__,
363 		    (size_t)zio->ipos, (size_t)zio->opos);
364 	}
365 
366 	/*
367 	 * Set up a temporary buffer for compressed data.  Use the size
368 	 * recommended by the zstd library; this is usually 128 kB, but
369 	 * just in case, make sure it's a multiple of the page size and no
370 	 * larger than MAXBSIZE.
371 	 */
372 	bsize = roundup(ZSTD_CStreamOutSize(), PAGE_SIZE);
373 	if (bsize > MAXBSIZE)
374 		bsize = MAXBSIZE;
375 	ibuf = malloc(bsize, M_TEMP, M_WAITOK);
376 	zib.src = NULL;
377 	zib.size = 0;
378 	zib.pos = 0;
379 
380 	/*
381 	 * Set up the decompression buffer.  If the target is not in
382 	 * kernel space, we will have to set up a bounce buffer.
383 	 *
384 	 * TODO: to avoid using a bounce buffer, map destination pages
385 	 * using vm_fault_quick_hold_pages().
386 	 */
387 	MPASS(zio->opos <= off);
388 	MPASS(uiop->uio_iovcnt == 1);
389 	MPASS(uiop->uio_iov->iov_len >= len);
390 	if (uiop->uio_segflg == UIO_SYSSPACE) {
391 		zob.dst = uiop->uio_iov->iov_base;
392 	} else {
393 		TARFS_DPF(BOUNCE, "%s: allocating %zu-byte bounce buffer\n",
394 		    __func__, len);
395 		zob.dst = obuf = malloc(len, M_TEMP, M_WAITOK);
396 	}
397 	zob.size = len;
398 	zob.pos = 0;
399 
400 	/* lock tarball */
401 	rl = vn_rangelock_rlock(tmp->vp, zio->ipos, OFF_MAX);
402 	error = vn_lock(tmp->vp, LK_SHARED);
403 	if (error != 0) {
404 		goto fail_unlocked;
405 	}
406 	/* check size */
407 	error = vn_getsize_locked(tmp->vp, &zsize, td->td_ucred);
408 	if (error != 0) {
409 		goto fail;
410 	}
411 	if (zio->ipos >= zsize) {
412 		/* beyond EOF */
413 		goto fail;
414 	}
415 
416 	while (resid > 0) {
417 		if (zib.pos == zib.size) {
418 			/* request data from the underlying file */
419 			aiov.iov_base = ibuf;
420 			aiov.iov_len = bsize;
421 			auio.uio_iov = &aiov;
422 			auio.uio_iovcnt = 1;
423 			auio.uio_offset = zio->ipos;
424 			auio.uio_segflg = UIO_SYSSPACE;
425 			auio.uio_rw = UIO_READ;
426 			auio.uio_resid = aiov.iov_len;
427 			auio.uio_td = td;
428 			error = VOP_READ(tmp->vp, &auio, IO_NODELOCKED,
429 			    td->td_ucred);
430 			if (error != 0)
431 				goto fail;
432 			TARFS_DPF(ZIO, "%s: req %zu+%zu got %zu+%zu\n", __func__,
433 			    (size_t)zio->ipos, bsize,
434 			    (size_t)zio->ipos, bsize - auio.uio_resid);
435 			zib.src = ibuf;
436 			zib.size = bsize - auio.uio_resid;
437 			zib.pos = 0;
438 		}
439 		MPASS(zib.pos <= zib.size);
440 		if (zib.pos == zib.size) {
441 			TARFS_DPF(ZIO, "%s: end of file after i %zu o %zu\n", __func__,
442 			    (size_t)zio->ipos, (size_t)zio->opos);
443 			goto fail;
444 		}
445 		if (zio->opos < off) {
446 			/* to be discarded */
447 			zob.size = min(off - zio->opos, len);
448 			zob.pos = 0;
449 		} else {
450 			zob.size = len;
451 			zob.pos = zio->opos - off;
452 		}
453 		ipos = zib.pos;
454 		opos = zob.pos;
455 		/* decompress as much as possible */
456 		zerror = ZSTD_decompressStream(zstd->zds, &zob, &zib);
457 		zio->ipos += ilen = zib.pos - ipos;
458 		zio->opos += olen = zob.pos - opos;
459 		if (zio->opos > off)
460 			resid -= olen;
461 		if (ZSTD_isError(zerror)) {
462 			TARFS_DPF(ZIO, "%s: inflate failed after i %zu o %zu: %s\n", __func__,
463 			    (size_t)zio->ipos, (size_t)zio->opos, ZSTD_getErrorName(zerror));
464 			error = EIO;
465 			goto fail;
466 		}
467 		if (zerror == 0 && olen == 0) {
468 			TARFS_DPF(ZIO, "%s: end of stream after i %zu o %zu\n", __func__,
469 			    (size_t)zio->ipos, (size_t)zio->opos);
470 			break;
471 		}
472 		if (zerror == 0) {
473 			TARFS_DPF(ZIO, "%s: end of frame after i %zu o %zu\n", __func__,
474 			    (size_t)zio->ipos, (size_t)zio->opos);
475 			tarfs_zio_update_index(zio, zio->ipos, zio->opos);
476 		}
477 		TARFS_DPF(ZIO, "%s: inflated %zu\n", __func__, olen);
478 #ifdef TARFS_DEBUG
479 		counter_u64_add(tarfs_zio_inflated, olen);
480 #endif
481 	}
482 fail:
483 	VOP_UNLOCK(tmp->vp);
484 fail_unlocked:
485 	if (error == 0) {
486 		if (uiop->uio_segflg == UIO_SYSSPACE) {
487 			uiop->uio_resid = resid;
488 		} else if (len > resid) {
489 			TARFS_DPF(BOUNCE, "%s: bounced %zu bytes\n", __func__,
490 			    len - resid);
491 			error = uiomove(obuf, len - resid, uiop);
492 #ifdef TARFS_DEBUG
493 			counter_u64_add(tarfs_zio_bounced, len - resid);
494 #endif
495 		}
496 	}
497 	if (obuf != NULL) {
498 		TARFS_DPF(BOUNCE, "%s: freeing bounce buffer\n", __func__);
499 		free(obuf, M_TEMP);
500 	}
501 	if (rl != NULL)
502 		vn_rangelock_unlock(tmp->vp, rl);
503 	if (ibuf != NULL)
504 		free(ibuf, M_TEMP);
505 	TARFS_DPF(ZIO, "%s(%zu, %zu) = %d (resid %zd)\n", __func__,
506 	    (size_t)off, len, error, uiop->uio_resid);
507 #ifdef TARFS_DEBUG
508 	counter_u64_add(tarfs_zio_consumed, len - uiop->uio_resid);
509 #endif
510 	if (error != 0) {
511 		zio->curidx = 0;
512 		zio->ipos = zio->idx[0].i;
513 		zio->opos = zio->idx[0].o;
514 		ZSTD_resetDStream(zstd->zds);
515 	}
516 	return (error);
517 }
518 #endif
519 
520 /*
521  * VOP_READ for zio node.
522  */
523 static int
tarfs_zread(struct vop_read_args * ap)524 tarfs_zread(struct vop_read_args *ap)
525 {
526 #if defined(TARFS_DEBUG) || defined(ZSTDIO)
527 	struct vnode *vp = ap->a_vp;
528 	struct tarfs_zio *zio = vp->v_data;
529 	struct uio *uiop = ap->a_uio;
530 #endif
531 #ifdef TARFS_DEBUG
532 	off_t off = uiop->uio_offset;
533 	size_t len = uiop->uio_resid;
534 #endif
535 	int error;
536 
537 	TARFS_DPF(ZIO, "%s(%zu, %zu)\n", __func__,
538 	    (size_t)off, len);
539 #ifdef ZSTDIO
540 	if (zio->zstd != NULL) {
541 		error = tarfs_zread_zstd(zio, uiop);
542 	} else
543 #endif
544 		error = EFTYPE;
545 	TARFS_DPF(ZIO, "%s(%zu, %zu) = %d (resid %zd)\n", __func__,
546 	    (size_t)off, len, error, uiop->uio_resid);
547 	return (error);
548 }
549 
550 /*
551  * VOP_RECLAIM for zio node.
552  */
553 static int
tarfs_zreclaim(struct vop_reclaim_args * ap)554 tarfs_zreclaim(struct vop_reclaim_args *ap)
555 {
556 	struct vnode *vp = ap->a_vp;
557 
558 	TARFS_DPF(ZIO, "%s(%p)\n", __func__, vp);
559 	vp->v_data = NULL;
560 	return (0);
561 }
562 
563 /*
564  * VOP_STRATEGY for zio node.
565  */
566 static int
tarfs_zstrategy(struct vop_strategy_args * ap)567 tarfs_zstrategy(struct vop_strategy_args *ap)
568 {
569 	struct uio auio;
570 	struct iovec iov;
571 	struct vnode *vp = ap->a_vp;
572 	struct buf *bp = ap->a_bp;
573 	off_t off;
574 	size_t len;
575 	int error;
576 
577 	iov.iov_base = bp->b_data;
578 	iov.iov_len = bp->b_bcount;
579 	off = bp->b_iooffset;
580 	len = bp->b_bcount;
581 	bp->b_resid = len;
582 	auio.uio_iov = &iov;
583 	auio.uio_iovcnt = 1;
584 	auio.uio_offset = off;
585 	auio.uio_resid = len;
586 	auio.uio_segflg = UIO_SYSSPACE;
587 	auio.uio_rw = UIO_READ;
588 	auio.uio_td = curthread;
589 	error = VOP_READ(vp, &auio, IO_DIRECT | IO_NODELOCKED, bp->b_rcred);
590 	bp->b_flags |= B_DONE;
591 	if (error != 0) {
592 		bp->b_ioflags |= BIO_ERROR;
593 		bp->b_error = error;
594 	}
595 	return (0);
596 }
597 
598 static struct vop_vector tarfs_znodeops = {
599 	.vop_default =		&default_vnodeops,
600 
601 	.vop_access =		tarfs_zaccess,
602 	.vop_getattr =		tarfs_zgetattr,
603 	.vop_read =		tarfs_zread,
604 	.vop_reclaim =		tarfs_zreclaim,
605 	.vop_strategy =		tarfs_zstrategy,
606 };
607 VFS_VOP_VECTOR_REGISTER(tarfs_znodeops);
608 
609 #ifdef TARFS_ZIO
610 /*
611  * Initializes the decompression layer.
612  */
613 static struct tarfs_zio *
tarfs_zio_init(struct tarfs_mount * tmp,off_t i,off_t o)614 tarfs_zio_init(struct tarfs_mount *tmp, off_t i, off_t o)
615 {
616 	struct tarfs_zio *zio;
617 	struct vnode *zvp;
618 
619 	zio = malloc(sizeof(*zio), M_TARFSZSTATE, M_ZERO | M_WAITOK);
620 	TARFS_DPF(ALLOC, "%s: allocated zio\n", __func__);
621 	zio->tmp = tmp;
622 	zio->szidx = 128;
623 	zio->idx = malloc(zio->szidx * sizeof(*zio->idx), M_TARFSZSTATE,
624 	    M_ZERO | M_WAITOK);
625 	zio->curidx = 0;
626 	zio->nidx = 1;
627 	zio->idx[zio->curidx].i = zio->ipos = i;
628 	zio->idx[zio->curidx].o = zio->opos = o;
629 	tmp->zio = zio;
630 	TARFS_DPF(ALLOC, "%s: allocated zio index\n", __func__);
631 	(void)getnewvnode("tarfsz", tmp->vfs, &tarfs_znodeops, &zvp);
632 	zvp->v_data = zio;
633 	zvp->v_type = VREG;
634 	zvp->v_mount = tmp->vfs;
635 	vn_set_state(zvp, VSTATE_CONSTRUCTED);
636 	tmp->znode = zvp;
637 	TARFS_DPF(ZIO, "%s: created zio node\n", __func__);
638 	return (zio);
639 }
640 #endif
641 
642 /*
643  * Initializes the I/O layer, including decompression if the signature of
644  * a supported compression format is detected.  Returns 0 on success and a
645  * positive errno value on failure.
646  */
647 int
tarfs_io_init(struct tarfs_mount * tmp)648 tarfs_io_init(struct tarfs_mount *tmp)
649 {
650 	uint8_t *block;
651 #ifdef TARFS_ZIO
652 	struct tarfs_zio *zio = NULL;
653 #endif
654 	ssize_t res;
655 	int error = 0;
656 
657 	block = malloc(tmp->iosize, M_TEMP, M_ZERO | M_WAITOK);
658 	res = tarfs_io_read_buf(tmp, true, block, 0, tmp->iosize);
659 	if (res < 0) {
660 		return (-res);
661 	}
662 	if (memcmp(block, XZ_MAGIC, sizeof(XZ_MAGIC)) == 0) {
663 		printf("xz compression not supported\n");
664 		error = EOPNOTSUPP;
665 		goto bad;
666 	} else if (memcmp(block, ZLIB_MAGIC, sizeof(ZLIB_MAGIC)) == 0) {
667 		printf("zlib compression not supported\n");
668 		error = EOPNOTSUPP;
669 		goto bad;
670 	} else if (memcmp(block, ZSTD_MAGIC, sizeof(ZSTD_MAGIC)) == 0) {
671 #ifdef ZSTDIO
672 		zio = tarfs_zio_init(tmp, 0, 0);
673 		zio->zstd = malloc(sizeof(*zio->zstd), M_TARFSZSTATE, M_WAITOK);
674 		zio->zstd->zds = ZSTD_createDStream_advanced(tarfs_zstd_mem);
675 		(void)ZSTD_initDStream(zio->zstd->zds);
676 #else
677 		printf("zstd compression not supported\n");
678 		error = EOPNOTSUPP;
679 		goto bad;
680 #endif
681 	}
682 bad:
683 	free(block, M_TEMP);
684 	return (error);
685 }
686 
687 #ifdef TARFS_ZIO
688 /*
689  * Tears down the decompression layer.
690  */
691 static int
tarfs_zio_fini(struct tarfs_mount * tmp)692 tarfs_zio_fini(struct tarfs_mount *tmp)
693 {
694 	struct tarfs_zio *zio = tmp->zio;
695 	int error = 0;
696 
697 	if (tmp->znode != NULL) {
698 		error = vn_lock(tmp->znode, LK_EXCLUSIVE);
699 		if (error != 0) {
700 			TARFS_DPF(ALLOC, "%s: failed to lock znode", __func__);
701 			return (error);
702 		}
703 		tmp->znode->v_mount = NULL;
704 		vgone(tmp->znode);
705 		vput(tmp->znode);
706 		tmp->znode = NULL;
707 	}
708 #ifdef ZSTDIO
709 	if (zio->zstd != NULL) {
710 		TARFS_DPF(ALLOC, "%s: freeing zstd state\n", __func__);
711 		ZSTD_freeDStream(zio->zstd->zds);
712 		free(zio->zstd, M_TARFSZSTATE);
713 	}
714 #endif
715 	if (zio->idx != NULL) {
716 		TARFS_DPF(ALLOC, "%s: freeing index\n", __func__);
717 		free(zio->idx, M_TARFSZSTATE);
718 	}
719 	TARFS_DPF(ALLOC, "%s: freeing zio\n", __func__);
720 	free(zio, M_TARFSZSTATE);
721 	tmp->zio = NULL;
722 	return (error);
723 }
724 #endif
725 
726 /*
727  * Tears down the I/O layer, including the decompression layer if
728  * applicable.
729  */
730 int
tarfs_io_fini(struct tarfs_mount * tmp)731 tarfs_io_fini(struct tarfs_mount *tmp)
732 {
733 	int error = 0;
734 
735 #ifdef TARFS_ZIO
736 	if (tmp->zio != NULL) {
737 		error = tarfs_zio_fini(tmp);
738 	}
739 #endif
740 	return (error);
741 }
742