/*
* 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) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2013, 2017 by Delphix. All rights reserved.
* Copyright 2014 HybridCluster. All rights reserved.
*/
#include <sys/dbuf.h>
#include <sys/dmu.h>
#include <sys/dmu_impl.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_tx.h>
#include <sys/dnode.h>
#include <sys/zap.h>
#include <sys/zfeature.h>
#include <sys/dsl_dataset.h>
/*
* Each of the concurrent object allocators will grab
* 2^dmu_object_alloc_chunk_shift dnode slots at a time. The default is to
* grab 128 slots, which is 4 blocks worth. This was experimentally
* determined to be the lowest value that eliminates the measurable effect
* of lock contention from this code path.
*/
int dmu_object_alloc_chunk_shift = 7;
static uint64_t
dmu_object_alloc_impl(objset_t *os, dmu_object_type_t ot, int blocksize,
int indirect_blockshift, dmu_object_type_t bonustype, int bonuslen,
int dnodesize, dnode_t **allocated_dnode, void *tag, dmu_tx_t *tx)
{
uint64_t object;
uint64_t L1_dnode_count = DNODES_PER_BLOCK <<
(DMU_META_DNODE(os)->dn_indblkshift - SPA_BLKPTRSHIFT);
dnode_t *dn = NULL;
int dn_slots = dnodesize >> DNODE_SHIFT;
boolean_t restarted = B_FALSE;
uint64_t *cpuobj = NULL;
int dnodes_per_chunk = 1 << dmu_object_alloc_chunk_shift;
int error;
kpreempt_disable();
cpuobj = &os->os_obj_next_percpu[CPU_SEQID %
os->os_obj_next_percpu_len];
kpreempt_enable();
if (dn_slots == 0) {
dn_slots = DNODE_MIN_SLOTS;
} else {
ASSERT3S(dn_slots, >=, DNODE_MIN_SLOTS);
ASSERT3S(dn_slots, <=, DNODE_MAX_SLOTS);
}
/*
* The "chunk" of dnodes that is assigned to a CPU-specific
* allocator needs to be at least one block's worth, to avoid
* lock contention on the dbuf. It can be at most one L1 block's
* worth, so that the "rescan after polishing off a L1's worth"
* logic below will be sure to kick in.
*/
if (dnodes_per_chunk < DNODES_PER_BLOCK)
dnodes_per_chunk = DNODES_PER_BLOCK;
if (dnodes_per_chunk > L1_dnode_count)
dnodes_per_chunk = L1_dnode_count;
/*
* The caller requested the dnode be returned as a performance
* optimization in order to avoid releasing the hold only to
* immediately reacquire it. Since they caller is responsible
* for releasing the hold they must provide the tag.
*/
if (allocated_dnode != NULL) {
ASSERT3P(tag, !=, NULL);
} else {
ASSERT3P(tag, ==, NULL);
tag = FTAG;
}
object = *cpuobj;
for (;;) {
/*
* If we finished a chunk of dnodes, get a new one from
* the global allocator.
*/
if ((P2PHASE(object, dnodes_per_chunk) == 0) ||
(P2PHASE(object + dn_slots - 1, dnodes_per_chunk) <
dn_slots)) {
DNODE_STAT_BUMP(dnode_alloc_next_chunk);
mutex_enter(&os->os_obj_lock);
ASSERT0(P2PHASE(os->os_obj_next_chunk,
dnodes_per_chunk));
object = os->os_obj_next_chunk;
/*
* Each time we polish off a L1 bp worth of dnodes
* (2^12 objects), move to another L1 bp that's
* still reasonably sparse (at most 1/4 full). Look
* from the beginning at most once per txg. If we
* still can't allocate from that L1 block, search
* for an empty L0 block, which will quickly skip
* to the end of the metadnode if no nearby L0
* blocks are empty. This fallback avoids a
* pathology where full dnode blocks containing
* large dnodes appear sparse because they have a
* low blk_fill, leading to many failed allocation
* attempts. In the long term a better mechanism to
* search for sparse metadnode regions, such as
* spacemaps, could be implemented.
*
* os_scan_dnodes is set during txg sync if enough
* objects have been freed since the previous
* rescan to justify backfilling again.
*
* Note that dmu_traverse depends on the behavior
* that we use multiple blocks of the dnode object
* before going back to reuse objects. Any change
* to this algorithm should preserve that property
* or find another solution to the issues described
* in traverse_visitbp.
*/
if (P2PHASE(object, L1_dnode_count) == 0) {
uint64_t offset;
uint64_t blkfill;
int minlvl;
if (os->os_rescan_dnodes) {
offset = 0;
os->os_rescan_dnodes = B_FALSE;
} else {
offset = object << DNODE_SHIFT;
}
blkfill = restarted ? 1 : DNODES_PER_BLOCK >> 2;
minlvl = restarted ? 1 : 2;
restarted = B_TRUE;
error = dnode_next_offset(DMU_META_DNODE(os),
DNODE_FIND_HOLE, &offset, minlvl,
blkfill, 0);
if (error == 0) {
object = offset >> DNODE_SHIFT;
}
}
/*
* Note: if "restarted", we may find a L0 that
* is not suitably aligned.
*/
os->os_obj_next_chunk =
P2ALIGN(object, dnodes_per_chunk) +
dnodes_per_chunk;
(void) atomic_swap_64(cpuobj, object);
mutex_exit(&os->os_obj_lock);
}
/*
* The value of (*cpuobj) before adding dn_slots is the object
* ID assigned to us. The value afterwards is the object ID
* assigned to whoever wants to do an allocation next.
*/
object = atomic_add_64_nv(cpuobj, dn_slots) - dn_slots;
/*
* XXX We should check for an i/o error here and return
* up to our caller. Actually we should pre-read it in
* dmu_tx_assign(), but there is currently no mechanism
* to do so.
*/
error = dnode_hold_impl(os, object, DNODE_MUST_BE_FREE,
dn_slots, tag, &dn);
if (error == 0) {
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
/*
* Another thread could have allocated it; check
* again now that we have the struct lock.
*/
if (dn->dn_type == DMU_OT_NONE) {
dnode_allocate(dn, ot, blocksize,
indirect_blockshift, bonustype,
bonuslen, dn_slots, tx);
rw_exit(&dn->dn_struct_rwlock);
dmu_tx_add_new_object(tx, dn);
/*
* Caller requested the allocated dnode be
* returned and is responsible for the hold.
*/
if (allocated_dnode != NULL)
*allocated_dnode = dn;
else
dnode_rele(dn, tag);
return (object);
}
rw_exit(&dn->dn_struct_rwlock);
dnode_rele(dn, tag);
DNODE_STAT_BUMP(dnode_alloc_race);
}
/*
* Skip to next known valid starting point on error. This
* is the start of the next block of dnodes.
*/
if (dmu_object_next(os, &object, B_TRUE, 0) != 0) {
object = P2ROUNDUP(object + 1, DNODES_PER_BLOCK);
DNODE_STAT_BUMP(dnode_alloc_next_block);
}
(void) atomic_swap_64(cpuobj, object);
}
}
uint64_t
dmu_object_alloc(objset_t *os, dmu_object_type_t ot, int blocksize,
dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
return dmu_object_alloc_impl(os, ot, blocksize, 0, bonustype,
bonuslen, 0, NULL, NULL, tx);
}
uint64_t
dmu_object_alloc_ibs(objset_t *os, dmu_object_type_t ot, int blocksize,
int indirect_blockshift, dmu_object_type_t bonustype, int bonuslen,
dmu_tx_t *tx)
{
return dmu_object_alloc_impl(os, ot, blocksize, indirect_blockshift,
bonustype, bonuslen, 0, NULL, NULL, tx);
}
uint64_t
dmu_object_alloc_dnsize(objset_t *os, dmu_object_type_t ot, int blocksize,
dmu_object_type_t bonustype, int bonuslen, int dnodesize, dmu_tx_t *tx)
{
return (dmu_object_alloc_impl(os, ot, blocksize, 0, bonustype,
bonuslen, dnodesize, NULL, NULL, tx));
}
/*
* Allocate a new object and return a pointer to the newly allocated dnode
* via the allocated_dnode argument. The returned dnode will be held and
* the caller is responsible for releasing the hold by calling dnode_rele().
*/
uint64_t
dmu_object_alloc_hold(objset_t *os, dmu_object_type_t ot, int blocksize,
int indirect_blockshift, dmu_object_type_t bonustype, int bonuslen,
int dnodesize, dnode_t **allocated_dnode, void *tag, dmu_tx_t *tx)
{
return (dmu_object_alloc_impl(os, ot, blocksize, indirect_blockshift,
bonustype, bonuslen, dnodesize, allocated_dnode, tag, tx));
}
int
dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
return (dmu_object_claim_dnsize(os, object, ot, blocksize, bonustype,
bonuslen, 0, tx));
}
int
dmu_object_claim_dnsize(objset_t *os, uint64_t object, dmu_object_type_t ot,
int blocksize, dmu_object_type_t bonustype, int bonuslen,
int dnodesize, dmu_tx_t *tx)
{
dnode_t *dn;
int dn_slots = dnodesize >> DNODE_SHIFT;
int err;
if (dn_slots == 0)
dn_slots = DNODE_MIN_SLOTS;
ASSERT3S(dn_slots, >=, DNODE_MIN_SLOTS);
ASSERT3S(dn_slots, <=, DNODE_MAX_SLOTS);
if (object == DMU_META_DNODE_OBJECT && !dmu_tx_private_ok(tx))
return (SET_ERROR(EBADF));
err = dnode_hold_impl(os, object, DNODE_MUST_BE_FREE, dn_slots,
FTAG, &dn);
if (err)
return (err);
dnode_allocate(dn, ot, blocksize, 0, bonustype, bonuslen, dn_slots, tx);
dmu_tx_add_new_object(tx, dn);
dnode_rele(dn, FTAG);
return (0);
}
int
dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
return (dmu_object_reclaim_dnsize(os, object, ot, blocksize, bonustype,
bonuslen, DNODE_MIN_SIZE, B_FALSE, tx));
}
int
dmu_object_reclaim_dnsize(objset_t *os, uint64_t object, dmu_object_type_t ot,
int blocksize, dmu_object_type_t bonustype, int bonuslen, int dnodesize,
boolean_t keep_spill, dmu_tx_t *tx)
{
dnode_t *dn;
int dn_slots = dnodesize >> DNODE_SHIFT;
int err;
if (dn_slots == 0)
dn_slots = DNODE_MIN_SLOTS;
if (object == DMU_META_DNODE_OBJECT)
return (SET_ERROR(EBADF));
err = dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0,
FTAG, &dn);
if (err)
return (err);
dnode_reallocate(dn, ot, blocksize, bonustype, bonuslen, dn_slots,
keep_spill, tx);
dnode_rele(dn, FTAG);
return (err);
}
int
dmu_object_rm_spill(objset_t *os, uint64_t object, dmu_tx_t *tx)
{
dnode_t *dn;
int err;
err = dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0,
FTAG, &dn);
if (err)
return (err);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
if (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
dbuf_rm_spill(dn, tx);
dnode_rm_spill(dn, tx);
}
rw_exit(&dn->dn_struct_rwlock);
dnode_rele(dn, FTAG);
return (err);
}
int
dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx)
{
dnode_t *dn;
int err;
ASSERT(object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx));
err = dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0,
FTAG, &dn);
if (err)
return (err);
ASSERT(dn->dn_type != DMU_OT_NONE);
/*
* If we don't create this free range, we'll leak indirect blocks when
* we get to freeing the dnode in syncing context.
*/
dnode_free_range(dn, 0, DMU_OBJECT_END, tx);
dnode_free(dn, tx);
dnode_rele(dn, FTAG);
return (0);
}
/*
* Return (in *objectp) the next object which is allocated (or a hole)
* after *object, taking into account only objects that may have been modified
* after the specified txg.
*/
int
dmu_object_next(objset_t *os, uint64_t *objectp, boolean_t hole, uint64_t txg)
{
uint64_t offset;
uint64_t start_obj;
struct dsl_dataset *ds = os->os_dsl_dataset;
int error;
if (*objectp == 0) {
start_obj = 1;
} else if (ds && dsl_dataset_feature_is_active(ds,
SPA_FEATURE_LARGE_DNODE)) {
uint64_t i = *objectp + 1;
uint64_t last_obj = *objectp | (DNODES_PER_BLOCK - 1);
dmu_object_info_t doi;
/*
* Scan through the remaining meta dnode block. The contents
* of each slot in the block are known so it can be quickly
* checked. If the block is exhausted without a match then
* hand off to dnode_next_offset() for further scanning.
*/
while (i <= last_obj) {
error = dmu_object_info(os, i, &doi);
if (error == ENOENT) {
if (hole) {
*objectp = i;
return (0);
} else {
i++;
}
} else if (error == EEXIST) {
i++;
} else if (error == 0) {
if (hole) {
i += doi.doi_dnodesize >> DNODE_SHIFT;
} else {
*objectp = i;
return (0);
}
} else {
return (error);
}
}
start_obj = i;
} else {
start_obj = *objectp + 1;
}
offset = start_obj << DNODE_SHIFT;
error = dnode_next_offset(DMU_META_DNODE(os),
(hole ? DNODE_FIND_HOLE : 0), &offset, 0, DNODES_PER_BLOCK, txg);
*objectp = offset >> DNODE_SHIFT;
return (error);
}
/*
* Turn this object from old_type into DMU_OTN_ZAP_METADATA, and bump the
* refcount on SPA_FEATURE_EXTENSIBLE_DATASET.
*
* Only for use from syncing context, on MOS objects.
*/
void
dmu_object_zapify(objset_t *mos, uint64_t object, dmu_object_type_t old_type,
dmu_tx_t *tx)
{
dnode_t *dn;
ASSERT(dmu_tx_is_syncing(tx));
VERIFY0(dnode_hold(mos, object, FTAG, &dn));
if (dn->dn_type == DMU_OTN_ZAP_METADATA) {
dnode_rele(dn, FTAG);
return;
}
ASSERT3U(dn->dn_type, ==, old_type);
ASSERT0(dn->dn_maxblkid);
/*
* We must initialize the ZAP data before changing the type,
* so that concurrent calls to *_is_zapified() can determine if
* the object has been completely zapified by checking the type.
*/
mzap_create_impl(dn, 0, 0, tx);
dn->dn_next_type[tx->tx_txg & TXG_MASK] = dn->dn_type =
DMU_OTN_ZAP_METADATA;
dnode_setdirty(dn, tx);
dnode_rele(dn, FTAG);
spa_feature_incr(dmu_objset_spa(mos),
SPA_FEATURE_EXTENSIBLE_DATASET, tx);
}
void
dmu_object_free_zapified(objset_t *mos, uint64_t object, dmu_tx_t *tx)
{
dnode_t *dn;
dmu_object_type_t t;
ASSERT(dmu_tx_is_syncing(tx));
VERIFY0(dnode_hold(mos, object, FTAG, &dn));
t = dn->dn_type;
dnode_rele(dn, FTAG);
if (t == DMU_OTN_ZAP_METADATA) {
spa_feature_decr(dmu_objset_spa(mos),
SPA_FEATURE_EXTENSIBLE_DATASET, tx);
}
VERIFY0(dmu_object_free(mos, object, tx));
}
EXPORT_SYMBOL(dmu_object_alloc);
EXPORT_SYMBOL(dmu_object_alloc_ibs);
EXPORT_SYMBOL(dmu_object_alloc_dnsize);
EXPORT_SYMBOL(dmu_object_alloc_hold);
EXPORT_SYMBOL(dmu_object_claim);
EXPORT_SYMBOL(dmu_object_claim_dnsize);
EXPORT_SYMBOL(dmu_object_reclaim);
EXPORT_SYMBOL(dmu_object_reclaim_dnsize);
EXPORT_SYMBOL(dmu_object_rm_spill);
EXPORT_SYMBOL(dmu_object_free);
EXPORT_SYMBOL(dmu_object_next);
EXPORT_SYMBOL(dmu_object_zapify);
EXPORT_SYMBOL(dmu_object_free_zapified);
/* BEGIN CSTYLED */
ZFS_MODULE_PARAM(zfs, , dmu_object_alloc_chunk_shift, INT, ZMOD_RW,
"CPU-specific allocator grabs 2^N objects at once");
/* END CSTYLED */
