bptree.c revision 9fa718d2f477620f14e3f2948dd03e3470add804
/*
* 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) 2012 by Delphix. All rights reserved.
*/
#include <sys/arc.h>
#include <sys/bptree.h>
#include <sys/dmu.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_traverse.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_pool.h>
#include <sys/dnode.h>
#include <sys/refcount.h>
#include <sys/spa.h>
/*
* A bptree is a queue of root block pointers from destroyed datasets. When a
* dataset is destroyed its root block pointer is put on the end of the pool's
* bptree queue so the dataset's blocks can be freed asynchronously by
* dsl_scan_sync. This allows the delete operation to finish without traversing
* all the dataset's blocks.
*
* Note that while bt_begin and bt_end are only ever incremented in this code
* they are effectively reset to 0 every time the entire bptree is freed because
* the bptree's object is destroyed and re-created.
*/
struct bptree_args {
bptree_phys_t *ba_phys; /* data in bonus buffer, dirtied if freeing */
boolean_t ba_free; /* true if freeing during traversal */
bptree_itor_t *ba_func; /* function to call for each blockpointer */
void *ba_arg; /* caller supplied argument to ba_func */
dmu_tx_t *ba_tx; /* caller supplied tx, NULL if not freeing */
} bptree_args_t;
uint64_t
bptree_alloc(objset_t *os, dmu_tx_t *tx)
{
uint64_t obj;
dmu_buf_t *db;
bptree_phys_t *bt;
obj = dmu_object_alloc(os, DMU_OTN_UINT64_METADATA,
SPA_MAXBLOCKSIZE, DMU_OTN_UINT64_METADATA,
sizeof (bptree_phys_t), tx);
/*
* Bonus buffer contents are already initialized to 0, but for
* readability we make it explicit.
*/
VERIFY0(dmu_bonus_hold(os, obj, FTAG, &db));
dmu_buf_will_dirty(db, tx);
bt = db->db_data;
bt->bt_begin = 0;
bt->bt_end = 0;
bt->bt_bytes = 0;
bt->bt_comp = 0;
bt->bt_uncomp = 0;
dmu_buf_rele(db, FTAG);
return (obj);
}
int
bptree_free(objset_t *os, uint64_t obj, dmu_tx_t *tx)
{
dmu_buf_t *db;
bptree_phys_t *bt;
VERIFY0(dmu_bonus_hold(os, obj, FTAG, &db));
bt = db->db_data;
ASSERT3U(bt->bt_begin, ==, bt->bt_end);
ASSERT0(bt->bt_bytes);
ASSERT0(bt->bt_comp);
ASSERT0(bt->bt_uncomp);
dmu_buf_rele(db, FTAG);
return (dmu_object_free(os, obj, tx));
}
void
bptree_add(objset_t *os, uint64_t obj, blkptr_t *bp, uint64_t birth_txg,
uint64_t bytes, uint64_t comp, uint64_t uncomp, dmu_tx_t *tx)
{
dmu_buf_t *db;
bptree_phys_t *bt;
bptree_entry_phys_t bte;
/*
* bptree objects are in the pool mos, therefore they can only be
* modified in syncing context. Furthermore, this is only modified
* by the sync thread, so no locking is necessary.
*/
ASSERT(dmu_tx_is_syncing(tx));
VERIFY0(dmu_bonus_hold(os, obj, FTAG, &db));
bt = db->db_data;
bte.be_birth_txg = birth_txg;
bte.be_bp = *bp;
bzero(&bte.be_zb, sizeof (bte.be_zb));
dmu_write(os, obj, bt->bt_end * sizeof (bte), sizeof (bte), &bte, tx);
dmu_buf_will_dirty(db, tx);
bt->bt_end++;
bt->bt_bytes += bytes;
bt->bt_comp += comp;
bt->bt_uncomp += uncomp;
dmu_buf_rele(db, FTAG);
}
/* ARGSUSED */
static int
bptree_visit_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)
{
int err;
struct bptree_args *ba = arg;
if (bp == NULL)
return (0);
err = ba->ba_func(ba->ba_arg, bp, ba->ba_tx);
if (err == 0 && ba->ba_free) {
ba->ba_phys->bt_bytes -= bp_get_dsize_sync(spa, bp);
ba->ba_phys->bt_comp -= BP_GET_PSIZE(bp);
ba->ba_phys->bt_uncomp -= BP_GET_UCSIZE(bp);
}
return (err);
}
int
bptree_iterate(objset_t *os, uint64_t obj, boolean_t free, bptree_itor_t func,
void *arg, dmu_tx_t *tx)
{
int err;
uint64_t i;
dmu_buf_t *db;
struct bptree_args ba;
ASSERT(!free || dmu_tx_is_syncing(tx));
err = dmu_bonus_hold(os, obj, FTAG, &db);
if (err != 0)
return (err);
if (free)
dmu_buf_will_dirty(db, tx);
ba.ba_phys = db->db_data;
ba.ba_free = free;
ba.ba_func = func;
ba.ba_arg = arg;
ba.ba_tx = tx;
err = 0;
for (i = ba.ba_phys->bt_begin; i < ba.ba_phys->bt_end; i++) {
bptree_entry_phys_t bte;
ASSERT(!free || i == ba.ba_phys->bt_begin);
err = dmu_read(os, obj, i * sizeof (bte), sizeof (bte),
&bte, DMU_READ_NO_PREFETCH);
if (err != 0)
break;
err = traverse_dataset_destroyed(os->os_spa, &bte.be_bp,
bte.be_birth_txg, &bte.be_zb, TRAVERSE_POST,
bptree_visit_cb, &ba);
if (free) {
ASSERT(err == 0 || err == ERESTART);
if (err != 0) {
/* save bookmark for future resume */
ASSERT3U(bte.be_zb.zb_objset, ==,
ZB_DESTROYED_OBJSET);
ASSERT0(bte.be_zb.zb_level);
dmu_write(os, obj, i * sizeof (bte),
sizeof (bte), &bte, tx);
break;
} else {
ba.ba_phys->bt_begin++;
(void) dmu_free_range(os, obj,
i * sizeof (bte), sizeof (bte), tx);
}
}
}
ASSERT(!free || err != 0 || ba.ba_phys->bt_begin == ba.ba_phys->bt_end);
/* if all blocks are free there should be no used space */
if (ba.ba_phys->bt_begin == ba.ba_phys->bt_end) {
ASSERT0(ba.ba_phys->bt_bytes);
ASSERT0(ba.ba_phys->bt_comp);
ASSERT0(ba.ba_phys->bt_uncomp);
}
dmu_buf_rele(db, FTAG);
return (err);
}