dmu_diff.c revision 288571 
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, 2014 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 file *da_fp;		/* 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	kthread_t *da_td;
49};
50
51static int
52write_bytes(struct diffarg *da)
53{
54	struct uio auio;
55	struct iovec aiov;
56
57	aiov.iov_base = (caddr_t)&da->da_ddr;
58	aiov.iov_len = sizeof (da->da_ddr);
59	auio.uio_iov = &aiov;
60	auio.uio_iovcnt = 1;
61	auio.uio_resid = aiov.iov_len;
62	auio.uio_segflg = UIO_SYSSPACE;
63	auio.uio_rw = UIO_WRITE;
64	auio.uio_offset = (off_t)-1;
65	auio.uio_td = da->da_td;
66#ifdef _KERNEL
67	if (da->da_fp->f_type == DTYPE_VNODE)
68		bwillwrite();
69	return (fo_write(da->da_fp, &auio, da->da_td->td_ucred, 0, da->da_td));
70#else
71	fprintf(stderr, "%s: returning EOPNOTSUPP\n", __func__);
72	return (EOPNOTSUPP);
73#endif
74}
75
76static int
77write_record(struct diffarg *da)
78{
79
80	if (da->da_ddr.ddr_type == DDR_NONE) {
81		da->da_err = 0;
82		return (0);
83	}
84
85	da->da_err = write_bytes(da);
86	*da->da_offp += sizeof (da->da_ddr);
87	return (da->da_err);
88}
89
90static int
91report_free_dnode_range(struct diffarg *da, uint64_t first, uint64_t last)
92{
93	ASSERT(first <= last);
94	if (da->da_ddr.ddr_type != DDR_FREE ||
95	    first != da->da_ddr.ddr_last + 1) {
96		if (write_record(da) != 0)
97			return (da->da_err);
98		da->da_ddr.ddr_type = DDR_FREE;
99		da->da_ddr.ddr_first = first;
100		da->da_ddr.ddr_last = last;
101		return (0);
102	}
103	da->da_ddr.ddr_last = last;
104	return (0);
105}
106
107static int
108report_dnode(struct diffarg *da, uint64_t object, dnode_phys_t *dnp)
109{
110	ASSERT(dnp != NULL);
111	if (dnp->dn_type == DMU_OT_NONE)
112		return (report_free_dnode_range(da, object, object));
113
114	if (da->da_ddr.ddr_type != DDR_INUSE ||
115	    object != da->da_ddr.ddr_last + 1) {
116		if (write_record(da) != 0)
117			return (da->da_err);
118		da->da_ddr.ddr_type = DDR_INUSE;
119		da->da_ddr.ddr_first = da->da_ddr.ddr_last = object;
120		return (0);
121	}
122	da->da_ddr.ddr_last = object;
123	return (0);
124}
125
126#define	DBP_SPAN(dnp, level)				  \
127	(((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
128	(level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
129
130/* ARGSUSED */
131static int
132diff_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
133    const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
134{
135	struct diffarg *da = arg;
136	int err = 0;
137
138	if (issig(JUSTLOOKING) && issig(FORREAL))
139		return (SET_ERROR(EINTR));
140
141	if (bp == NULL || zb->zb_object != DMU_META_DNODE_OBJECT)
142		return (0);
143
144	if (BP_IS_HOLE(bp)) {
145		uint64_t span = DBP_SPAN(dnp, zb->zb_level);
146		uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
147
148		err = report_free_dnode_range(da, dnobj,
149		    dnobj + (span >> DNODE_SHIFT) - 1);
150		if (err)
151			return (err);
152	} else if (zb->zb_level == 0) {
153		dnode_phys_t *blk;
154		arc_buf_t *abuf;
155		arc_flags_t aflags = ARC_FLAG_WAIT;
156		int blksz = BP_GET_LSIZE(bp);
157		int i;
158
159		if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
160		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL,
161		    &aflags, zb) != 0)
162			return (SET_ERROR(EIO));
163
164		blk = abuf->b_data;
165		for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
166			uint64_t dnobj = (zb->zb_blkid <<
167			    (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
168			err = report_dnode(da, dnobj, blk+i);
169			if (err)
170				break;
171		}
172		(void) arc_buf_remove_ref(abuf, &abuf);
173		if (err)
174			return (err);
175		/* Don't care about the data blocks */
176		return (TRAVERSE_VISIT_NO_CHILDREN);
177	}
178	return (0);
179}
180
181int
182dmu_diff(const char *tosnap_name, const char *fromsnap_name,
183#ifdef illumos
184    struct vnode *vp, offset_t *offp)
185#else
186    struct file *fp, offset_t *offp)
187#endif
188{
189	struct diffarg da;
190	dsl_dataset_t *fromsnap;
191	dsl_dataset_t *tosnap;
192	dsl_pool_t *dp;
193	int error;
194	uint64_t fromtxg;
195
196	if (strchr(tosnap_name, '@') == NULL ||
197	    strchr(fromsnap_name, '@') == NULL)
198		return (SET_ERROR(EINVAL));
199
200	error = dsl_pool_hold(tosnap_name, FTAG, &dp);
201	if (error != 0)
202		return (error);
203
204	error = dsl_dataset_hold(dp, tosnap_name, FTAG, &tosnap);
205	if (error != 0) {
206		dsl_pool_rele(dp, FTAG);
207		return (error);
208	}
209
210	error = dsl_dataset_hold(dp, fromsnap_name, FTAG, &fromsnap);
211	if (error != 0) {
212		dsl_dataset_rele(tosnap, FTAG);
213		dsl_pool_rele(dp, FTAG);
214		return (error);
215	}
216
217	if (!dsl_dataset_is_before(tosnap, fromsnap, 0)) {
218		dsl_dataset_rele(fromsnap, FTAG);
219		dsl_dataset_rele(tosnap, FTAG);
220		dsl_pool_rele(dp, FTAG);
221		return (SET_ERROR(EXDEV));
222	}
223
224	fromtxg = dsl_dataset_phys(fromsnap)->ds_creation_txg;
225	dsl_dataset_rele(fromsnap, FTAG);
226
227	dsl_dataset_long_hold(tosnap, FTAG);
228	dsl_pool_rele(dp, FTAG);
229
230	da.da_fp = fp;
231	da.da_offp = offp;
232	da.da_ddr.ddr_type = DDR_NONE;
233	da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
234	da.da_err = 0;
235	da.da_td = curthread;
236
237	error = traverse_dataset(tosnap, fromtxg,
238	    TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA, diff_cb, &da);
239
240	if (error != 0) {
241		da.da_err = error;
242	} else {
243		/* we set the da.da_err we return as side-effect */
244		(void) write_record(&da);
245	}
246
247	dsl_dataset_long_rele(tosnap, FTAG);
248	dsl_dataset_rele(tosnap, FTAG);
249
250	return (da.da_err);
251}
252