xref: /illumos-gate/usr/src/uts/common/fs/zfs/dmu_diff.c (revision 99d3b4e271d47a93935645d0c2d348d161f90c80)
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  * 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 
44 struct diffarg {
45 	struct vnode *da_vp;		/* file to which we are reporting */
46 	offset_t *da_offp;
47 	int da_err;			/* error that stopped diff search */
48 	dmu_diff_record_t da_ddr;
49 };
50 
51 static int
write_record(struct diffarg * da)52 write_record(struct diffarg *da)
53 {
54 	ssize_t resid; /* have to get resid to get detailed errno */
55 
56 	if (da->da_ddr.ddr_type == DDR_NONE) {
57 		da->da_err = 0;
58 		return (0);
59 	}
60 
61 	da->da_err = vn_rdwr(UIO_WRITE, da->da_vp, (caddr_t)&da->da_ddr,
62 	    sizeof (da->da_ddr), 0, UIO_SYSSPACE, FAPPEND,
63 	    RLIM64_INFINITY, CRED(), &resid);
64 	*da->da_offp += sizeof (da->da_ddr);
65 	return (da->da_err);
66 }
67 
68 static int
report_free_dnode_range(struct diffarg * da,uint64_t first,uint64_t last)69 report_free_dnode_range(struct diffarg *da, uint64_t first, uint64_t last)
70 {
71 	ASSERT(first <= last);
72 	if (da->da_ddr.ddr_type != DDR_FREE ||
73 	    first != da->da_ddr.ddr_last + 1) {
74 		if (write_record(da) != 0)
75 			return (da->da_err);
76 		da->da_ddr.ddr_type = DDR_FREE;
77 		da->da_ddr.ddr_first = first;
78 		da->da_ddr.ddr_last = last;
79 		return (0);
80 	}
81 	da->da_ddr.ddr_last = last;
82 	return (0);
83 }
84 
85 static int
report_dnode(struct diffarg * da,uint64_t object,dnode_phys_t * dnp)86 report_dnode(struct diffarg *da, uint64_t object, dnode_phys_t *dnp)
87 {
88 	ASSERT(dnp != NULL);
89 	if (dnp->dn_type == DMU_OT_NONE)
90 		return (report_free_dnode_range(da, object, object));
91 
92 	if (da->da_ddr.ddr_type != DDR_INUSE ||
93 	    object != da->da_ddr.ddr_last + 1) {
94 		if (write_record(da) != 0)
95 			return (da->da_err);
96 		da->da_ddr.ddr_type = DDR_INUSE;
97 		da->da_ddr.ddr_first = da->da_ddr.ddr_last = object;
98 		return (0);
99 	}
100 	da->da_ddr.ddr_last = object;
101 	return (0);
102 }
103 
104 #define	DBP_SPAN(dnp, level)				  \
105 	(((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
106 	(level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
107 
108 /* ARGSUSED */
109 static int
diff_cb(spa_t * spa,zilog_t * zilog,const blkptr_t * bp,const zbookmark_phys_t * zb,const dnode_phys_t * dnp,void * arg)110 diff_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
111     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
112 {
113 	struct diffarg *da = arg;
114 	int err = 0;
115 
116 	if (issig(JUSTLOOKING) && issig(FORREAL))
117 		return (SET_ERROR(EINTR));
118 
119 	if (bp == NULL || zb->zb_object != DMU_META_DNODE_OBJECT)
120 		return (0);
121 
122 	if (BP_IS_HOLE(bp)) {
123 		uint64_t span = DBP_SPAN(dnp, zb->zb_level);
124 		uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
125 
126 		err = report_free_dnode_range(da, dnobj,
127 		    dnobj + (span >> DNODE_SHIFT) - 1);
128 		if (err)
129 			return (err);
130 	} else if (zb->zb_level == 0) {
131 		dnode_phys_t *blk;
132 		arc_buf_t *abuf;
133 		arc_flags_t aflags = ARC_FLAG_WAIT;
134 		int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
135 		int zio_flags = ZIO_FLAG_CANFAIL;
136 		int i;
137 
138 		if (BP_IS_PROTECTED(bp))
139 			zio_flags |= ZIO_FLAG_RAW;
140 
141 		if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
142 		    ZIO_PRIORITY_ASYNC_READ, zio_flags, &aflags, zb) != 0)
143 			return (SET_ERROR(EIO));
144 
145 		blk = abuf->b_data;
146 		for (i = 0; i < epb; i += blk[i].dn_extra_slots + 1) {
147 			uint64_t dnobj = (zb->zb_blkid <<
148 			    (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
149 			err = report_dnode(da, dnobj, blk+i);
150 			if (err)
151 				break;
152 		}
153 		arc_buf_destroy(abuf, &abuf);
154 		if (err)
155 			return (err);
156 		/* Don't care about the data blocks */
157 		return (TRAVERSE_VISIT_NO_CHILDREN);
158 	}
159 	return (0);
160 }
161 
162 int
dmu_diff(const char * tosnap_name,const char * fromsnap_name,struct vnode * vp,offset_t * offp)163 dmu_diff(const char *tosnap_name, const char *fromsnap_name,
164     struct vnode *vp, offset_t *offp)
165 {
166 	struct diffarg da;
167 	dsl_dataset_t *fromsnap;
168 	dsl_dataset_t *tosnap;
169 	dsl_pool_t *dp;
170 	int error;
171 	uint64_t fromtxg;
172 
173 	if (strchr(tosnap_name, '@') == NULL ||
174 	    strchr(fromsnap_name, '@') == NULL)
175 		return (SET_ERROR(EINVAL));
176 
177 	error = dsl_pool_hold(tosnap_name, FTAG, &dp);
178 	if (error != 0)
179 		return (error);
180 
181 	error = dsl_dataset_hold(dp, tosnap_name, FTAG, &tosnap);
182 	if (error != 0) {
183 		dsl_pool_rele(dp, FTAG);
184 		return (error);
185 	}
186 
187 	error = dsl_dataset_hold(dp, fromsnap_name, FTAG, &fromsnap);
188 	if (error != 0) {
189 		dsl_dataset_rele(tosnap, FTAG);
190 		dsl_pool_rele(dp, FTAG);
191 		return (error);
192 	}
193 
194 	if (!dsl_dataset_is_before(tosnap, fromsnap, 0)) {
195 		dsl_dataset_rele(fromsnap, FTAG);
196 		dsl_dataset_rele(tosnap, FTAG);
197 		dsl_pool_rele(dp, FTAG);
198 		return (SET_ERROR(EXDEV));
199 	}
200 
201 	fromtxg = dsl_dataset_phys(fromsnap)->ds_creation_txg;
202 	dsl_dataset_rele(fromsnap, FTAG);
203 
204 	dsl_dataset_long_hold(tosnap, FTAG);
205 	dsl_pool_rele(dp, FTAG);
206 
207 	da.da_vp = vp;
208 	da.da_offp = offp;
209 	da.da_ddr.ddr_type = DDR_NONE;
210 	da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
211 	da.da_err = 0;
212 
213 	/*
214 	 * Since zfs diff only looks at dnodes which are stored in plaintext
215 	 * (other than bonus buffers), we don't technically need to decrypt
216 	 * the dataset to perform this operation. However, the command line
217 	 * utility will still fail if the keys are not loaded because the
218 	 * dataset isn't mounted and because it will fail when it attempts to
219 	 * call the ZFS_IOC_OBJ_TO_STATS ioctl.
220 	 */
221 	error = traverse_dataset(tosnap, fromtxg,
222 	    TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA | TRAVERSE_NO_DECRYPT,
223 	    diff_cb, &da);
224 
225 	if (error != 0) {
226 		da.da_err = error;
227 	} else {
228 		/* we set the da.da_err we return as side-effect */
229 		(void) write_record(&da);
230 	}
231 
232 	dsl_dataset_long_rele(tosnap, FTAG);
233 	dsl_dataset_rele(tosnap, FTAG);
234 
235 	return (da.da_err);
236 }
237