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 https://opensource.org/licenses/CDDL-1.0.
  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, 2018 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 #include <sys/zfs_file.h>
  44
  45
  46 typedef struct dmu_diffarg {
  47         zfs_file_t *da_fp;              /* file to which we are reporting */
  48         offset_t *da_offp;
  49         int da_err;                     /* error that stopped diff search */
  50         dmu_diff_record_t da_ddr;
  51 } dmu_diffarg_t;
  52
  53 static int
  54 write_record(dmu_diffarg_t *da)
  55 {
  56         zfs_file_t *fp;
  57         ssize_t resid;
  58
  59         if (da->da_ddr.ddr_type == DDR_NONE) {
  60                 da->da_err = 0;
  61                 return (0);
  62         }
  63
  64         fp = da->da_fp;
  65         da->da_err = zfs_file_write(fp, (caddr_t)&da->da_ddr,
  66             sizeof (da->da_ddr), &resid);
  67         *da->da_offp += sizeof (da->da_ddr);
  68         return (da->da_err);
  69 }
  70
  71 static int
  72 report_free_dnode_range(dmu_diffarg_t *da, uint64_t first, uint64_t last)
  73 {
  74         ASSERT(first <= last);
  75         if (da->da_ddr.ddr_type != DDR_FREE ||
  76             first != da->da_ddr.ddr_last + 1) {
  77                 if (write_record(da) != 0)
  78                         return (da->da_err);
  79                 da->da_ddr.ddr_type = DDR_FREE;
  80                 da->da_ddr.ddr_first = first;
  81                 da->da_ddr.ddr_last = last;
  82                 return (0);
  83         }
  84         da->da_ddr.ddr_last = last;
  85         return (0);
  86 }
  87
  88 static int
  89 report_dnode(dmu_diffarg_t *da, uint64_t object, dnode_phys_t *dnp)
  90 {
  91         ASSERT(dnp != NULL);
  92         if (dnp->dn_type == DMU_OT_NONE)
  93                 return (report_free_dnode_range(da, object, object));
  94
  95         if (da->da_ddr.ddr_type != DDR_INUSE ||
  96             object != da->da_ddr.ddr_last + 1) {
  97                 if (write_record(da) != 0)
  98                         return (da->da_err);
  99                 da->da_ddr.ddr_type = DDR_INUSE;
 100                 da->da_ddr.ddr_first = da->da_ddr.ddr_last = object;
 101                 return (0);
 102         }
 103         da->da_ddr.ddr_last = object;
 104         return (0);
 105 }
 106
 107 #define DBP_SPAN(dnp, level)                              \
 108         (((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
 109         (level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
 110
 111 static int
 112 diff_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 113     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 114 {
 115         (void) zilog;
 116         dmu_diffarg_t *da = arg;
 117         int err = 0;
 118
 119         if (issig())
 120                 return (SET_ERROR(EINTR));
 121
 122         if (zb->zb_level == ZB_DNODE_LEVEL ||
 123             zb->zb_object != DMU_META_DNODE_OBJECT)
 124                 return (0);
 125
 126         if (BP_IS_HOLE(bp)) {
 127                 uint64_t span = DBP_SPAN(dnp, zb->zb_level);
 128                 uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
 129
 130                 err = report_free_dnode_range(da, dnobj,
 131                     dnobj + (span >> DNODE_SHIFT) - 1);
 132                 if (err)
 133                         return (err);
 134         } else if (zb->zb_level == 0) {
 135                 dnode_phys_t *blk;
 136                 arc_buf_t *abuf;
 137                 arc_flags_t aflags = ARC_FLAG_WAIT;
 138                 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
 139                 int zio_flags = ZIO_FLAG_CANFAIL;
 140                 int i;
 141
 142                 if (BP_IS_PROTECTED(bp))
 143                         zio_flags |= ZIO_FLAG_RAW;
 144
 145                 if (arc_read(NULL, spa, bp, arc_getbuf_func, &abuf,
 146                     ZIO_PRIORITY_ASYNC_READ, zio_flags, &aflags, zb) != 0)
 147                         return (SET_ERROR(EIO));
 148
 149                 blk = abuf->b_data;
 150                 for (i = 0; i < epb; i += blk[i].dn_extra_slots + 1) {
 151                         uint64_t dnobj = (zb->zb_blkid <<
 152                             (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
 153                         err = report_dnode(da, dnobj, blk+i);
 154                         if (err)
 155                                 break;
 156                 }
 157                 arc_buf_destroy(abuf, &abuf);
 158                 if (err)
 159                         return (err);
 160                 /* Don't care about the data blocks */
 161                 return (TRAVERSE_VISIT_NO_CHILDREN);
 162         }
 163         return (0);
 164 }
 165
 166 int
 167 dmu_diff(const char *tosnap_name, const char *fromsnap_name,
 168     zfs_file_t *fp, offset_t *offp)
 169 {
 170         dmu_diffarg_t da;
 171         dsl_dataset_t *fromsnap;
 172         dsl_dataset_t *tosnap;
 173         dsl_pool_t *dp;
 174         int error;
 175         uint64_t fromtxg;
 176
 177         if (strchr(tosnap_name, '@') == NULL ||
 178             strchr(fromsnap_name, '@') == NULL)
 179                 return (SET_ERROR(EINVAL));
 180
 181         error = dsl_pool_hold(tosnap_name, FTAG, &dp);
 182         if (error != 0)
 183                 return (error);
 184
 185         error = dsl_dataset_hold(dp, tosnap_name, FTAG, &tosnap);
 186         if (error != 0) {
 187                 dsl_pool_rele(dp, FTAG);
 188                 return (error);
 189         }
 190
 191         error = dsl_dataset_hold(dp, fromsnap_name, FTAG, &fromsnap);
 192         if (error != 0) {
 193                 dsl_dataset_rele(tosnap, FTAG);
 194                 dsl_pool_rele(dp, FTAG);
 195                 return (error);
 196         }
 197
 198         if (!dsl_dataset_is_before(tosnap, fromsnap, 0)) {
 199                 dsl_dataset_rele(fromsnap, FTAG);
 200                 dsl_dataset_rele(tosnap, FTAG);
 201                 dsl_pool_rele(dp, FTAG);
 202                 return (SET_ERROR(EXDEV));
 203         }
 204
 205         fromtxg = dsl_dataset_phys(fromsnap)->ds_creation_txg;
 206         dsl_dataset_rele(fromsnap, FTAG);
 207
 208         dsl_dataset_long_hold(tosnap, FTAG);
 209         dsl_pool_rele(dp, FTAG);
 210
 211         da.da_fp = fp;
 212         da.da_offp = offp;
 213         da.da_ddr.ddr_type = DDR_NONE;
 214         da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
 215         da.da_err = 0;
 216
 217         /*
 218          * Since zfs diff only looks at dnodes which are stored in plaintext
 219          * (other than bonus buffers), we don't technically need to decrypt
 220          * the dataset to perform this operation. However, the command line
 221          * utility will still fail if the keys are not loaded because the
 222          * dataset isn't mounted and because it will fail when it attempts to
 223          * call the ZFS_IOC_OBJ_TO_STATS ioctl.
 224          */
 225         error = traverse_dataset(tosnap, fromtxg,
 226             TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA | TRAVERSE_NO_DECRYPT,
 227             diff_cb, &da);
 228
 229         if (error != 0) {
 230                 da.da_err = error;
 231         } else {
 232                 /* we set the da.da_err we return as side-effect */
 233                 (void) write_record(&da);
 234         }
 235
 236         dsl_dataset_long_rele(tosnap, FTAG);
 237         dsl_dataset_rele(tosnap, FTAG);
 238
 239         return (da.da_err);
 240 }