1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or https://opensource.org/licenses/CDDL-1.0.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
24 * Copyright (c) 2019, loli10K <ezomori.nozomu@gmail.com>. All rights reserved.
25 */
26
27#include <sys/dmu.h>
28#include <sys/dmu_impl.h>
29#include <sys/dmu_tx.h>
30#include <sys/dbuf.h>
31#include <sys/dnode.h>
32#include <sys/zfs_context.h>
33#include <sys/dmu_objset.h>
34#include <sys/dmu_traverse.h>
35#include <sys/dsl_dataset.h>
36#include <sys/dsl_dir.h>
37#include <sys/dsl_pool.h>
38#include <sys/dsl_synctask.h>
39#include <sys/zfs_ioctl.h>
40#include <sys/zap.h>
41#include <sys/zio_checksum.h>
42#include <sys/zfs_znode.h>
43#include <sys/zfs_file.h>
44
45
46typedef struct dmu_diffarg {
47	zfs_file_t *da_fp;		/* file to which we are reporting */
48	offset_t *da_offp;
49	int da_err;			/* error that stopped diff search */
50	dmu_diff_record_t da_ddr;
51} dmu_diffarg_t;
52
53static int
54write_record(dmu_diffarg_t *da)
55{
56	zfs_file_t *fp;
57	ssize_t resid;
58
59	if (da->da_ddr.ddr_type == DDR_NONE) {
60		da->da_err = 0;
61		return (0);
62	}
63
64	fp = da->da_fp;
65	da->da_err = zfs_file_write(fp, (caddr_t)&da->da_ddr,
66	    sizeof (da->da_ddr), &resid);
67	*da->da_offp += sizeof (da->da_ddr);
68	return (da->da_err);
69}
70
71static int
72report_free_dnode_range(dmu_diffarg_t *da, uint64_t first, uint64_t last)
73{
74	ASSERT(first <= last);
75	if (da->da_ddr.ddr_type != DDR_FREE ||
76	    first != da->da_ddr.ddr_last + 1) {
77		if (write_record(da) != 0)
78			return (da->da_err);
79		da->da_ddr.ddr_type = DDR_FREE;
80		da->da_ddr.ddr_first = first;
81		da->da_ddr.ddr_last = last;
82		return (0);
83	}
84	da->da_ddr.ddr_last = last;
85	return (0);
86}
87
88static int
89report_dnode(dmu_diffarg_t *da, uint64_t object, dnode_phys_t *dnp)
90{
91	ASSERT(dnp != NULL);
92	if (dnp->dn_type == DMU_OT_NONE)
93		return (report_free_dnode_range(da, object, object));
94
95	if (da->da_ddr.ddr_type != DDR_INUSE ||
96	    object != da->da_ddr.ddr_last + 1) {
97		if (write_record(da) != 0)
98			return (da->da_err);
99		da->da_ddr.ddr_type = DDR_INUSE;
100		da->da_ddr.ddr_first = da->da_ddr.ddr_last = object;
101		return (0);
102	}
103	da->da_ddr.ddr_last = object;
104	return (0);
105}
106
107#define	DBP_SPAN(dnp, level)				  \
108	(((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
109	(level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
110
111static int
112diff_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
113    const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
114{
115	(void) zilog;
116	dmu_diffarg_t *da = arg;
117	int err = 0;
118
119	if (issig())
120		return (SET_ERROR(EINTR));
121
122	if (zb->zb_level == ZB_DNODE_LEVEL ||
123	    zb->zb_object != DMU_META_DNODE_OBJECT)
124		return (0);
125
126	if (BP_IS_HOLE(bp)) {
127		uint64_t span = DBP_SPAN(dnp, zb->zb_level);
128		uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
129
130		err = report_free_dnode_range(da, dnobj,
131		    dnobj + (span >> DNODE_SHIFT) - 1);
132		if (err)
133			return (err);
134	} else if (zb->zb_level == 0) {
135		dnode_phys_t *blk;
136		arc_buf_t *abuf;
137		arc_flags_t aflags = ARC_FLAG_WAIT;
138		int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
139		int zio_flags = ZIO_FLAG_CANFAIL;
140		int i;
141
142		if (BP_IS_PROTECTED(bp))
143			zio_flags |= ZIO_FLAG_RAW;
144
145		if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
146		    ZIO_PRIORITY_ASYNC_READ, zio_flags, &aflags, zb) != 0)
147			return (SET_ERROR(EIO));
148
149		blk = abuf->b_data;
150		for (i = 0; i < epb; i += blk[i].dn_extra_slots + 1) {
151			uint64_t dnobj = (zb->zb_blkid <<
152			    (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
153			err = report_dnode(da, dnobj, blk+i);
154			if (err)
155				break;
156		}
157		arc_buf_destroy(abuf, &abuf);
158		if (err)
159			return (err);
160		/* Don't care about the data blocks */
161		return (TRAVERSE_VISIT_NO_CHILDREN);
162	}
163	return (0);
164}
165
166int
167dmu_diff(const char *tosnap_name, const char *fromsnap_name,
168    zfs_file_t *fp, offset_t *offp)
169{
170	dmu_diffarg_t da;
171	dsl_dataset_t *fromsnap;
172	dsl_dataset_t *tosnap;
173	dsl_pool_t *dp;
174	int error;
175	uint64_t fromtxg;
176
177	if (strchr(tosnap_name, '@') == NULL ||
178	    strchr(fromsnap_name, '@') == NULL)
179		return (SET_ERROR(EINVAL));
180
181	error = dsl_pool_hold(tosnap_name, FTAG, &dp);
182	if (error != 0)
183		return (error);
184
185	error = dsl_dataset_hold(dp, tosnap_name, FTAG, &tosnap);
186	if (error != 0) {
187		dsl_pool_rele(dp, FTAG);
188		return (error);
189	}
190
191	error = dsl_dataset_hold(dp, fromsnap_name, FTAG, &fromsnap);
192	if (error != 0) {
193		dsl_dataset_rele(tosnap, FTAG);
194		dsl_pool_rele(dp, FTAG);
195		return (error);
196	}
197
198	if (!dsl_dataset_is_before(tosnap, fromsnap, 0)) {
199		dsl_dataset_rele(fromsnap, FTAG);
200		dsl_dataset_rele(tosnap, FTAG);
201		dsl_pool_rele(dp, FTAG);
202		return (SET_ERROR(EXDEV));
203	}
204
205	fromtxg = dsl_dataset_phys(fromsnap)->ds_creation_txg;
206	dsl_dataset_rele(fromsnap, FTAG);
207
208	dsl_dataset_long_hold(tosnap, FTAG);
209	dsl_pool_rele(dp, FTAG);
210
211	da.da_fp = fp;
212	da.da_offp = offp;
213	da.da_ddr.ddr_type = DDR_NONE;
214	da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
215	da.da_err = 0;
216
217	/*
218	 * Since zfs diff only looks at dnodes which are stored in plaintext
219	 * (other than bonus buffers), we don't technically need to decrypt
220	 * the dataset to perform this operation. However, the command line
221	 * utility will still fail if the keys are not loaded because the
222	 * dataset isn't mounted and because it will fail when it attempts to
223	 * call the ZFS_IOC_OBJ_TO_STATS ioctl.
224	 */
225	error = traverse_dataset(tosnap, fromtxg,
226	    TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA | TRAVERSE_NO_DECRYPT,
227	    diff_cb, &da);
228
229	if (error != 0) {
230		da.da_err = error;
231	} else {
232		/* we set the da.da_err we return as side-effect */
233		(void) write_record(&da);
234	}
235
236	dsl_dataset_long_rele(tosnap, FTAG);
237	dsl_dataset_rele(tosnap, FTAG);
238
239	return (da.da_err);
240}
241