dmu_diff.c revision 99d5e173470cf967aa87653364ed614299e7b511
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
*/
#include <sys/dmu.h>
#include <sys/dmu_impl.h>
#include <sys/dmu_tx.h>
#include <sys/dbuf.h>
#include <sys/dnode.h>
#include <sys/zfs_context.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_traverse.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_synctask.h>
#include <sys/zfs_ioctl.h>
#include <sys/zap.h>
#include <sys/zio_checksum.h>
#include <sys/zfs_znode.h>
struct diffarg {
struct vnode *da_vp; /* file to which we are reporting */
offset_t *da_offp;
int da_err; /* error that stopped diff search */
dmu_diff_record_t da_ddr;
};
static int
write_record(struct diffarg *da)
{
ssize_t resid; /* have to get resid to get detailed errno */
if (da->da_ddr.ddr_type == DDR_NONE) {
da->da_err = 0;
return (0);
}
da->da_err = vn_rdwr(UIO_WRITE, da->da_vp, (caddr_t)&da->da_ddr,
sizeof (da->da_ddr), 0, UIO_SYSSPACE, FAPPEND,
RLIM64_INFINITY, CRED(), &resid);
*da->da_offp += sizeof (da->da_ddr);
return (da->da_err);
}
static int
report_free_dnode_range(struct diffarg *da, uint64_t first, uint64_t last)
{
ASSERT(first <= last);
if (da->da_ddr.ddr_type != DDR_FREE ||
first != da->da_ddr.ddr_last + 1) {
if (write_record(da) != 0)
return (da->da_err);
da->da_ddr.ddr_type = DDR_FREE;
da->da_ddr.ddr_first = first;
da->da_ddr.ddr_last = last;
return (0);
}
da->da_ddr.ddr_last = last;
return (0);
}
static int
report_dnode(struct diffarg *da, uint64_t object, dnode_phys_t *dnp)
{
ASSERT(dnp != NULL);
if (dnp->dn_type == DMU_OT_NONE)
return (report_free_dnode_range(da, object, object));
if (da->da_ddr.ddr_type != DDR_INUSE ||
object != da->da_ddr.ddr_last + 1) {
if (write_record(da) != 0)
return (da->da_err);
da->da_ddr.ddr_type = DDR_INUSE;
da->da_ddr.ddr_first = da->da_ddr.ddr_last = object;
return (0);
}
da->da_ddr.ddr_last = object;
return (0);
}
#define DBP_SPAN(dnp, level) \
(((uint64_t)dnp->dn_datablkszsec) << (SPA_MINBLOCKSHIFT + \
(level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)))
/* ARGSUSED */
static int
diff_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf,
const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
{
struct diffarg *da = arg;
int err = 0;
if (issig(JUSTLOOKING) && issig(FORREAL))
return (EINTR);
if (zb->zb_object != DMU_META_DNODE_OBJECT)
return (0);
if (bp == NULL) {
uint64_t span = DBP_SPAN(dnp, zb->zb_level);
uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
err = report_free_dnode_range(da, dnobj,
dnobj + (span >> DNODE_SHIFT) - 1);
if (err)
return (err);
} else if (zb->zb_level == 0) {
dnode_phys_t *blk;
arc_buf_t *abuf;
uint32_t aflags = ARC_WAIT;
int blksz = BP_GET_LSIZE(bp);
int i;
if (dsl_read(NULL, spa, bp, pbuf,
arc_getbuf_func, &abuf, ZIO_PRIORITY_ASYNC_READ,
ZIO_FLAG_CANFAIL, &aflags, zb) != 0)
return (EIO);
blk = abuf->b_data;
for (i = 0; i < blksz >> DNODE_SHIFT; i++) {
uint64_t dnobj = (zb->zb_blkid <<
(DNODE_BLOCK_SHIFT - DNODE_SHIFT)) + i;
err = report_dnode(da, dnobj, blk+i);
if (err)
break;
}
(void) arc_buf_remove_ref(abuf, &abuf);
if (err)
return (err);
/* Don't care about the data blocks */
return (TRAVERSE_VISIT_NO_CHILDREN);
}
return (0);
}
int
dmu_diff(objset_t *tosnap, objset_t *fromsnap, struct vnode *vp, offset_t *offp)
{
struct diffarg da;
dsl_dataset_t *ds = tosnap->os_dsl_dataset;
dsl_dataset_t *fromds = fromsnap->os_dsl_dataset;
dsl_dataset_t *findds;
dsl_dataset_t *relds;
int err = 0;
/* make certain we are looking at snapshots */
if (!dsl_dataset_is_snapshot(ds) || !dsl_dataset_is_snapshot(fromds))
return (EINVAL);
/* fromsnap must be earlier and from the same lineage as tosnap */
if (fromds->ds_phys->ds_creation_txg >= ds->ds_phys->ds_creation_txg)
return (EXDEV);
relds = NULL;
findds = ds;
while (fromds->ds_dir != findds->ds_dir) {
dsl_pool_t *dp = ds->ds_dir->dd_pool;
if (!dsl_dir_is_clone(findds->ds_dir)) {
if (relds)
dsl_dataset_rele(relds, FTAG);
return (EXDEV);
}
rw_enter(&dp->dp_config_rwlock, RW_READER);
err = dsl_dataset_hold_obj(dp,
findds->ds_dir->dd_phys->dd_origin_obj, FTAG, &findds);
rw_exit(&dp->dp_config_rwlock);
if (relds)
dsl_dataset_rele(relds, FTAG);
if (err)
return (EXDEV);
relds = findds;
}
if (relds)
dsl_dataset_rele(relds, FTAG);
da.da_vp = vp;
da.da_offp = offp;
da.da_ddr.ddr_type = DDR_NONE;
da.da_ddr.ddr_first = da.da_ddr.ddr_last = 0;
da.da_err = 0;
err = traverse_dataset(ds, fromds->ds_phys->ds_creation_txg,
TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA, diff_cb, &da);
if (err) {
da.da_err = err;
} else {
/* we set the da.da_err we return as side-effect */
(void) write_record(&da);
}
return (da.da_err);
}