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 http://www.opensolaris.org/os/licensing.
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, 2015 by Delphix. All rights reserved.
24 */
25
26#include <sys/dmu.h>
27#include <sys/dmu_impl.h>
28#include <sys/dmu_tx.h>
29#include <sys/dbuf.h>
30#include <sys/dnode.h>
31#include <sys/zfs_context.h>
32#include <sys/dmu_objset.h>
33#include <sys/dmu_traverse.h>
34#include <sys/dsl_dataset.h>
35#include <sys/dsl_dir.h>
36#include <sys/dsl_pool.h>
37#include <sys/dsl_synctask.h>
38#include <sys/zfs_ioctl.h>
39#include <sys/zap.h>
40#include <sys/zio_checksum.h>
41#include <sys/zfs_znode.h>
42
43struct diffarg {
44	struct vnode *da_vp;		/* file to which we are reporting */
45	offset_t *da_offp;
46	int da_err;			/* error that stopped diff search */
47	dmu_diff_record_t da_ddr;
48};
49
50static int
51write_record(struct diffarg *da)
52{
53	ssize_t resid; /* have to get resid to get detailed errno */
54
55	if (da->da_ddr.ddr_type == DDR_NONE) {
56		da->da_err = 0;
57		return (0);
58	}
59
60	da->da_err = vn_rdwr(UIO_WRITE, da->da_vp, (caddr_t)&da->da_ddr,
61	    sizeof (da->da_ddr), 0, UIO_SYSSPACE, FAPPEND,
62	    RLIM64_INFINITY, CRED(), &resid);
63	*da->da_offp += sizeof (da->da_ddr);
64	return (da->da_err);
65}
66
67static int
68report_free_dnode_range(struct diffarg *da, uint64_t first, uint64_t last)
69{
70	ASSERT(first <= last);
71	if (da->da_ddr.ddr_type != DDR_FREE ||
72	    first != da->da_ddr.ddr_last + 1) {
73		if (write_record(da) != 0)
74			return (da->da_err);
75		da->da_ddr.ddr_type = DDR_FREE;
76		da->da_ddr.ddr_first = first;
77		da->da_ddr.ddr_last = last;
78		return (0);
79	}
80	da->da_ddr.ddr_last = last;
81	return (0);
82}
83
84static int
85report_dnode(struct diffarg *da, uint64_t object, dnode_phys_t *dnp)
86{
87	ASSERT(dnp != NULL);
88	if (dnp->dn_type == DMU_OT_NONE)
89		return (report_free_dnode_range(da, object, object));
90
91	if (da->da_ddr.ddr_type != DDR_INUSE ||
92	    object != da->da_ddr.ddr_last + 1) {
93		if (write_record(da) != 0)
94			return (da->da_err);
95		da->da_ddr.ddr_type = DDR_INUSE;
96		da->da_ddr.ddr_first = da->da_ddr.ddr_last = object;
97		return (0);
98	}
99	da->da_ddr.ddr_last = object;
100	return (0);
101}
102
103#define	DBP_SPAN(dnp, level)				  \
104	(((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
105	(level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
106
107/* ARGSUSED */
108static int
109diff_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
110    const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
111{
112	struct diffarg *da = arg;
113	int err = 0;
114
115	if (issig(JUSTLOOKING) && issig(FORREAL))
116		return (SET_ERROR(EINTR));
117
118	if (bp == NULL || zb->zb_object != DMU_META_DNODE_OBJECT)
119		return (0);
120
121	if (BP_IS_HOLE(bp)) {
122		uint64_t span = DBP_SPAN(dnp, zb->zb_level);
123		uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
124
125		err = report_free_dnode_range(da, dnobj,
126		    dnobj + (span >> DNODE_SHIFT) - 1);
127		if (err)
128			return (err);
129	} else if (zb->zb_level == 0) {
130		dnode_phys_t *blk;
131		arc_buf_t *abuf;
132		arc_flags_t aflags = ARC_FLAG_WAIT;
133		int blksz = BP_GET_LSIZE(bp);
134		int zio_flags = ZIO_FLAG_CANFAIL;
135		int i;
136
137		if (BP_IS_PROTECTED(bp))
138			zio_flags |= ZIO_FLAG_RAW;
139
140		if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
141		    ZIO_PRIORITY_ASYNC_READ, zio_flags, &aflags, zb) != 0)
142			return (SET_ERROR(EIO));
143
144		blk = abuf->b_data;
145		for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
146			uint64_t dnobj = (zb->zb_blkid <<
147			    (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
148			err = report_dnode(da, dnobj, blk+i);
149			if (err)
150				break;
151		}
152		arc_buf_destroy(abuf, &abuf);
153		if (err)
154			return (err);
155		/* Don't care about the data blocks */
156		return (TRAVERSE_VISIT_NO_CHILDREN);
157	}
158	return (0);
159}
160
161int
162dmu_diff(const char *tosnap_name, const char *fromsnap_name,
163    struct vnode *vp, offset_t *offp)
164{
165	struct diffarg da;
166	dsl_dataset_t *fromsnap;
167	dsl_dataset_t *tosnap;
168	dsl_pool_t *dp;
169	int error;
170	uint64_t fromtxg;
171
172	if (strchr(tosnap_name, '@') == NULL ||
173	    strchr(fromsnap_name, '@') == NULL)
174		return (SET_ERROR(EINVAL));
175
176	error = dsl_pool_hold(tosnap_name, FTAG, &dp);
177	if (error != 0)
178		return (error);
179
180	error = dsl_dataset_hold(dp, tosnap_name, FTAG, &tosnap);
181	if (error != 0) {
182		dsl_pool_rele(dp, FTAG);
183		return (error);
184	}
185
186	error = dsl_dataset_hold(dp, fromsnap_name, FTAG, &fromsnap);
187	if (error != 0) {
188		dsl_dataset_rele(tosnap, FTAG);
189		dsl_pool_rele(dp, FTAG);
190		return (error);
191	}
192
193	if (!dsl_dataset_is_before(tosnap, fromsnap, 0)) {
194		dsl_dataset_rele(fromsnap, FTAG);
195		dsl_dataset_rele(tosnap, FTAG);
196		dsl_pool_rele(dp, FTAG);
197		return (SET_ERROR(EXDEV));
198	}
199
200	fromtxg = dsl_dataset_phys(fromsnap)->ds_creation_txg;
201	dsl_dataset_rele(fromsnap, FTAG);
202
203	dsl_dataset_long_hold(tosnap, FTAG);
204	dsl_pool_rele(dp, FTAG);
205
206	da.da_vp = vp;
207	da.da_offp = offp;
208	da.da_ddr.ddr_type = DDR_NONE;
209	da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
210	da.da_err = 0;
211
212	/*
213	 * Since zfs diff only looks at dnodes which are stored in plaintext
214	 * (other than bonus buffers), we don't technically need to decrypt
215	 * the dataset to perform this operation. However, the command line
216	 * utility will still fail if the keys are not loaded because the
217	 * dataset isn't mounted and because it will fail when it attempts to
218	 * call the ZFS_IOC_OBJ_TO_STATS ioctl.
219	 */
220	error = traverse_dataset(tosnap, fromtxg,
221	    TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA | TRAVERSE_NO_DECRYPT,
222	    diff_cb, &da);
223
224	if (error != 0) {
225		da.da_err = error;
226	} else {
227		/* we set the da.da_err we return as side-effect */
228		(void) write_record(&da);
229	}
230
231	dsl_dataset_long_rele(tosnap, FTAG);
232	dsl_dataset_rele(tosnap, FTAG);
233
234	return (da.da_err);
235}
236