usr/src/uts/common/fs/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  */
  24
  25 #include <sys/dmu.h>
  26 #include <sys/dmu_impl.h>
  27 #include <sys/dmu_tx.h>
  28 #include <sys/dbuf.h>
  29 #include <sys/dnode.h>
  30 #include <sys/zfs_context.h>
  31 #include <sys/dmu_objset.h>
  32 #include <sys/dmu_traverse.h>
  33 #include <sys/dsl_dataset.h>
  34 #include <sys/dsl_dir.h>
  35 #include <sys/dsl_pool.h>
  36 #include <sys/dsl_synctask.h>
  37 #include <sys/zfs_ioctl.h>
  38 #include <sys/zap.h>
  39 #include <sys/zio_checksum.h>
  40 #include <sys/zfs_znode.h>
  41
  42 struct diffarg {
  43         struct vnode *da_vp;            /* file to which we are reporting */
  44         offset_t *da_offp;
  45         int da_err;                     /* error that stopped diff search */
  46         dmu_diff_record_t da_ddr;
  47 };
  48
  49 static int
  50 write_record(struct diffarg *da)
  51 {
  52         ssize_t resid; /* have to get resid to get detailed errno */
  53
  54         if (da->da_ddr.ddr_type == DDR_NONE) {
  55                 da->da_err = 0;
  56                 return (0);
  57         }
  58
  59         da->da_err = vn_rdwr(UIO_WRITE, da->da_vp, (caddr_t)&da->da_ddr,
  60             sizeof (da->da_ddr), 0, UIO_SYSSPACE, FAPPEND,
  61             RLIM64_INFINITY, CRED(), &resid);
  62         *da->da_offp += sizeof (da->da_ddr);
  63         return (da->da_err);
  64 }
  65
  66 static int
  67 report_free_dnode_range(struct diffarg *da, uint64_t first, uint64_t last)
  68 {
  69         ASSERT(first <= last);
  70         if (da->da_ddr.ddr_type != DDR_FREE ||
  71             first != da->da_ddr.ddr_last + 1) {
  72                 if (write_record(da) != 0)
  73                         return (da->da_err);
  74                 da->da_ddr.ddr_type = DDR_FREE;
  75                 da->da_ddr.ddr_first = first;
  76                 da->da_ddr.ddr_last = last;
  77                 return (0);
  78         }
  79         da->da_ddr.ddr_last = last;
  80         return (0);
  81 }
  82
  83 static int
  84 report_dnode(struct diffarg *da, uint64_t object, dnode_phys_t *dnp)
  85 {
  86         ASSERT(dnp != NULL);
  87         if (dnp->dn_type == DMU_OT_NONE)
  88                 return (report_free_dnode_range(da, object, object));
  89
  90         if (da->da_ddr.ddr_type != DDR_INUSE ||
  91             object != da->da_ddr.ddr_last + 1) {
  92                 if (write_record(da) != 0)
  93                         return (da->da_err);
  94                 da->da_ddr.ddr_type = DDR_INUSE;
  95                 da->da_ddr.ddr_first = da->da_ddr.ddr_last = object;
  96                 return (0);
  97         }
  98         da->da_ddr.ddr_last = object;
  99         return (0);
 100 }
 101
 102 #define DBP_SPAN(dnp, level)                              \
 103         (((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
 104         (level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
 105
 106 /* ARGSUSED */
 107 static int
 108 diff_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
 109     const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 110 {
 111         struct diffarg *da = arg;
 112         int err = 0;
 113
 114         if (issig(JUSTLOOKING) && issig(FORREAL))
 115                 return (EINTR);
 116
 117         if (zb->zb_object != DMU_META_DNODE_OBJECT)
 118                 return (0);
 119
 120         if (bp == NULL) {
 121                 uint64_t span = DBP_SPAN(dnp, zb->zb_level);
 122                 uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
 123
 124                 err = report_free_dnode_range(da, dnobj,
 125                     dnobj + (span >> DNODE_SHIFT) - 1);
 126                 if (err)
 127                         return (err);
 128         } else if (zb->zb_level == 0) {
 129                 dnode_phys_t *blk;
 130                 arc_buf_t *abuf;
 131                 uint32_t aflags = ARC_WAIT;
 132                 int blksz = BP_GET_LSIZE(bp);
 133                 int i;
 134
 135                 if (dsl_read(NULL, spa, bp, pbuf,
 136                     arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
 137                     ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
 138                         return (EIO);
 139
 140                 blk = abuf->b_data;
 141                 for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
 142                         uint64_t dnobj = (zb->zb_blkid <<
 143                             (DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
 144                         err = report_dnode(da, dnobj, blk+i);
 145                         if (err)
 146                                 break;
 147                 }
 148                 (void) arc_buf_remove_ref(abuf, &abuf);
 149                 if (err)
 150                         return (err);
 151                 /* Don't care about the data blocks */
 152                 return (TRAVERSE_VISIT_NO_CHILDREN);
 153         }
 154         return (0);
 155 }
 156
 157 int
 158 dmu_diff(objset_t *tosnap, objset_t *fromsnap, struct vnode *vp, offset_t *offp)
 159 {
 160         struct diffarg da;
 161         dsl_dataset_t *ds = tosnap->os_dsl_dataset;
 162         dsl_dataset_t *fromds = fromsnap->os_dsl_dataset;
 163         dsl_dataset_t *findds;
 164         dsl_dataset_t *relds;
 165         int err = 0;
 166
 167         /* make certain we are looking at snapshots */
 168         if (!dsl_dataset_is_snapshot(ds) || !dsl_dataset_is_snapshot(fromds))
 169                 return (EINVAL);
 170
 171         /* fromsnap must be earlier and from the same lineage as tosnap */
 172         if (fromds->ds_phys->ds_creation_txg >= ds->ds_phys->ds_creation_txg)
 173                 return (EXDEV);
 174
 175         relds = NULL;
 176         findds = ds;
 177
 178         while (fromds->ds_dir != findds->ds_dir) {
 179                 dsl_pool_t *dp = ds->ds_dir->dd_pool;
 180
 181                 if (!dsl_dir_is_clone(findds->ds_dir)) {
 182                         if (relds)
 183                                 dsl_dataset_rele(relds, FTAG);
 184                         return (EXDEV);
 185                 }
 186
 187                 rw_enter(&dp->dp_config_rwlock, RW_READER);
 188                 err = dsl_dataset_hold_obj(dp,
 189                     findds->ds_dir->dd_phys->dd_origin_obj, FTAG, &findds);
 190                 rw_exit(&dp->dp_config_rwlock);
 191
 192                 if (relds)
 193                         dsl_dataset_rele(relds, FTAG);
 194
 195                 if (err)
 196                         return (EXDEV);
 197
 198                 relds = findds;
 199         }
 200
 201         if (relds)
 202                 dsl_dataset_rele(relds, FTAG);
 203
 204         da.da_vp = vp;
 205         da.da_offp = offp;
 206         da.da_ddr.ddr_type = DDR_NONE;
 207         da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
 208         da.da_err = 0;
 209
 210         err = traverse_dataset(ds, fromds->ds_phys->ds_creation_txg,
 211             TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA, diff_cb, &da);
 212
 213         if (err) {
 214                 da.da_err = err;
 215         } else {
 216                 /* we set the da.da_err we return as side-effect */
 217                 (void) write_record(&da);
 218         }
 219
 220         return (da.da_err);
 221 }