module/zfs/dmu_diff.c

   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
  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
  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
  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
 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 (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                 uint32_t aflags = ARC_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
 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 = fromsnap->ds_phys->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 }