xref: /titanic_41/usr/src/uts/common/fs/zfs/dmu_diff.c (revision 5f9bb2f350e19a276d3aff33afb5fc94fb47f02a)
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 
43 struct 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 
50 static int
write_record(struct diffarg * da)51 write_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 
67 static int
report_free_dnode_range(struct diffarg * da,uint64_t first,uint64_t last)68 report_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 
84 static int
report_dnode(struct diffarg * da,uint64_t object,dnode_phys_t * dnp)85 report_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 */
108 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)109 diff_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 i;
135 
136 		if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
137 		    ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL,
138 		    &aflags, zb) != 0)
139 			return (SET_ERROR(EIO));
140 
141 		blk = abuf->b_data;
142 		for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
143 			uint64_t dnobj = (zb->zb_blkid <<
144 			    (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
145 			err = report_dnode(da, dnobj, blk+i);
146 			if (err)
147 				break;
148 		}
149 		(void) arc_buf_remove_ref(abuf, &abuf);
150 		if (err)
151 			return (err);
152 		/* Don't care about the data blocks */
153 		return (TRAVERSE_VISIT_NO_CHILDREN);
154 	}
155 	return (0);
156 }
157 
158 int
dmu_diff(const char * tosnap_name,const char * fromsnap_name,struct vnode * vp,offset_t * offp)159 dmu_diff(const char *tosnap_name, const char *fromsnap_name,
160     struct vnode *vp, offset_t *offp)
161 {
162 	struct diffarg da;
163 	dsl_dataset_t *fromsnap;
164 	dsl_dataset_t *tosnap;
165 	dsl_pool_t *dp;
166 	int error;
167 	uint64_t fromtxg;
168 
169 	if (strchr(tosnap_name, '@') == NULL ||
170 	    strchr(fromsnap_name, '@') == NULL)
171 		return (SET_ERROR(EINVAL));
172 
173 	error = dsl_pool_hold(tosnap_name, FTAG, &dp);
174 	if (error != 0)
175 		return (error);
176 
177 	error = dsl_dataset_hold(dp, tosnap_name, FTAG, &tosnap);
178 	if (error != 0) {
179 		dsl_pool_rele(dp, FTAG);
180 		return (error);
181 	}
182 
183 	error = dsl_dataset_hold(dp, fromsnap_name, FTAG, &fromsnap);
184 	if (error != 0) {
185 		dsl_dataset_rele(tosnap, FTAG);
186 		dsl_pool_rele(dp, FTAG);
187 		return (error);
188 	}
189 
190 	if (!dsl_dataset_is_before(tosnap, fromsnap, 0)) {
191 		dsl_dataset_rele(fromsnap, FTAG);
192 		dsl_dataset_rele(tosnap, FTAG);
193 		dsl_pool_rele(dp, FTAG);
194 		return (SET_ERROR(EXDEV));
195 	}
196 
197 	fromtxg = dsl_dataset_phys(fromsnap)->ds_creation_txg;
198 	dsl_dataset_rele(fromsnap, FTAG);
199 
200 	dsl_dataset_long_hold(tosnap, FTAG);
201 	dsl_pool_rele(dp, FTAG);
202 
203 	da.da_vp = vp;
204 	da.da_offp = offp;
205 	da.da_ddr.ddr_type = DDR_NONE;
206 	da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
207 	da.da_err = 0;
208 
209 	error = traverse_dataset(tosnap, fromtxg,
210 	    TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA, diff_cb, &da);
211 
212 	if (error != 0) {
213 		da.da_err = error;
214 	} else {
215 		/* we set the da.da_err we return as side-effect */
216 		(void) write_record(&da);
217 	}
218 
219 	dsl_dataset_long_rele(tosnap, FTAG);
220 	dsl_dataset_rele(tosnap, FTAG);
221 
222 	return (da.da_err);
223 }
224