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freebsd-nq/module/zfs/dnode.c
Brian Behlendorf 3ec3bc2167 OpenZFS 7793 - ztest fails assertion in dmu_tx_willuse_space 
Reviewed by: Steve Gonczi <steve.gonczi@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>

Background information: This assertion about tx_space_* verifies that we
are not dirtying more stuff than we thought we would. We “need” to know
how much we will dirty so that we can check if we should fail this
transaction with ENOSPC/EDQUOT, in dmu_tx_assign(). While the
transaction is open (i.e. between dmu_tx_assign() and dmu_tx_commit() —
typically less than a millisecond), we call dbuf_dirty() on the exact
blocks that will be modified. Once this happens, the temporary
accounting in tx_space_* is unnecessary, because we know exactly what
blocks are newly dirtied; we call dnode_willuse_space() to track this
more exact accounting.

The fundamental problem causing this bug is that dmu_tx_hold_*() relies
on the current state in the DMU (e.g. dn_nlevels) to predict how much
will be dirtied by this transaction, but this state can change before we
actually perform the transaction (i.e. call dbuf_dirty()).

This bug will be fixed by removing the assertion that the tx_space_*
accounting is perfectly accurate (i.e. we never dirty more than was
predicted by dmu_tx_hold_*()). By removing the requirement that this
accounting be perfectly accurate, we can also vastly simplify it, e.g.
removing most of the logic in dmu_tx_count_*().

The new tx space accounting will be very approximate, and may be more or
less than what is actually dirtied. It will still be used to determine
if this transaction will put us over quota. Transactions that are marked
by dmu_tx_mark_netfree() will be excepted from this check. We won’t make
an attempt to determine how much space will be freed by the transaction
— this was rarely accurate enough to determine if a transaction should
be permitted when we are over quota, which is why dmu_tx_mark_netfree()
was introduced in 2014.

We also won’t attempt to give “credit” when overwriting existing blocks,
if those blocks may be freed. This allows us to remove the
do_free_accounting logic in dbuf_dirty(), and associated routines. This
logic attempted to predict what will be on disk when this txg syncs, to
know if the overwritten block will be freed (i.e. exists, and has no
snapshots).

OpenZFS-issue: https://www.illumos.org/issues/7793
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3704e0a
Upstream bugs: DLPX-32883a
Closes #5804 

Porting notes:
- DNODE_SIZE replaced with DNODE_MIN_SIZE in dmu_tx_count_dnode(),
  Using the default dnode size would be slightly better.
- DEBUG_DMU_TX wrappers and configure option removed.
- Resolved _by_dnode() conflicts these changes have not yet been
  applied to OpenZFS.
2017-03-07 09:51:59 -08:00

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/*
* 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) 2012, 2016 by Delphix. All rights reserved.
* Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
*/
#include <sys/zfs_context.h>
#include <sys/dbuf.h>
#include <sys/dnode.h>
#include <sys/dmu.h>
#include <sys/dmu_impl.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_objset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_dataset.h>
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/dmu_zfetch.h>
#include <sys/range_tree.h>
#include <sys/trace_dnode.h>
static kmem_cache_t *dnode_cache;
/*
* Define DNODE_STATS to turn on statistic gathering. By default, it is only
* turned on when DEBUG is also defined.
*/
#ifdef DEBUG
#define DNODE_STATS
#endif /* DEBUG */
#ifdef DNODE_STATS
#define DNODE_STAT_ADD(stat) ((stat)++)
#else
#define DNODE_STAT_ADD(stat) /* nothing */
#endif /* DNODE_STATS */
ASSERTV(static dnode_phys_t dnode_phys_zero);
int zfs_default_bs = SPA_MINBLOCKSHIFT;
int zfs_default_ibs = DN_MAX_INDBLKSHIFT;
#ifdef _KERNEL
static kmem_cbrc_t dnode_move(void *, void *, size_t, void *);
#endif /* _KERNEL */
static int
dbuf_compare(const void *x1, const void *x2)
{
const dmu_buf_impl_t *d1 = x1;
const dmu_buf_impl_t *d2 = x2;
int cmp = AVL_CMP(d1->db_level, d2->db_level);
if (likely(cmp))
return (cmp);
cmp = AVL_CMP(d1->db_blkid, d2->db_blkid);
if (likely(cmp))
return (cmp);
if (d1->db_state == DB_SEARCH) {
ASSERT3S(d2->db_state, !=, DB_SEARCH);
return (-1);
} else if (d2->db_state == DB_SEARCH) {
ASSERT3S(d1->db_state, !=, DB_SEARCH);
return (1);
}
return (AVL_PCMP(d1, d2));
}
/* ARGSUSED */
static int
dnode_cons(void *arg, void *unused, int kmflag)
{
dnode_t *dn = arg;
int i;
rw_init(&dn->dn_struct_rwlock, NULL, RW_NOLOCKDEP, NULL);
mutex_init(&dn->dn_mtx, NULL, MUTEX_DEFAULT, NULL);
mutex_init(&dn->dn_dbufs_mtx, NULL, MUTEX_DEFAULT, NULL);
cv_init(&dn->dn_notxholds, NULL, CV_DEFAULT, NULL);
/*
* Every dbuf has a reference, and dropping a tracked reference is
* O(number of references), so don't track dn_holds.
*/
refcount_create_untracked(&dn->dn_holds);
refcount_create(&dn->dn_tx_holds);
list_link_init(&dn->dn_link);
bzero(&dn->dn_next_nblkptr[0], sizeof (dn->dn_next_nblkptr));
bzero(&dn->dn_next_nlevels[0], sizeof (dn->dn_next_nlevels));
bzero(&dn->dn_next_indblkshift[0], sizeof (dn->dn_next_indblkshift));
bzero(&dn->dn_next_bonustype[0], sizeof (dn->dn_next_bonustype));
bzero(&dn->dn_rm_spillblk[0], sizeof (dn->dn_rm_spillblk));
bzero(&dn->dn_next_bonuslen[0], sizeof (dn->dn_next_bonuslen));
bzero(&dn->dn_next_blksz[0], sizeof (dn->dn_next_blksz));
for (i = 0; i < TXG_SIZE; i++) {
list_link_init(&dn->dn_dirty_link[i]);
dn->dn_free_ranges[i] = NULL;
list_create(&dn->dn_dirty_records[i],
sizeof (dbuf_dirty_record_t),
offsetof(dbuf_dirty_record_t, dr_dirty_node));
}
dn->dn_allocated_txg = 0;
dn->dn_free_txg = 0;
dn->dn_assigned_txg = 0;
dn->dn_dirtyctx = 0;
dn->dn_dirtyctx_firstset = NULL;
dn->dn_bonus = NULL;
dn->dn_have_spill = B_FALSE;
dn->dn_zio = NULL;
dn->dn_oldused = 0;
dn->dn_oldflags = 0;
dn->dn_olduid = 0;
dn->dn_oldgid = 0;
dn->dn_newuid = 0;
dn->dn_newgid = 0;
dn->dn_id_flags = 0;
dn->dn_dbufs_count = 0;
avl_create(&dn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t),
offsetof(dmu_buf_impl_t, db_link));
dn->dn_moved = 0;
return (0);
}
/* ARGSUSED */
static void
dnode_dest(void *arg, void *unused)
{
int i;
dnode_t *dn = arg;
rw_destroy(&dn->dn_struct_rwlock);
mutex_destroy(&dn->dn_mtx);
mutex_destroy(&dn->dn_dbufs_mtx);
cv_destroy(&dn->dn_notxholds);
refcount_destroy(&dn->dn_holds);
refcount_destroy(&dn->dn_tx_holds);
ASSERT(!list_link_active(&dn->dn_link));
for (i = 0; i < TXG_SIZE; i++) {
ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
ASSERT3P(dn->dn_free_ranges[i], ==, NULL);
list_destroy(&dn->dn_dirty_records[i]);
ASSERT0(dn->dn_next_nblkptr[i]);
ASSERT0(dn->dn_next_nlevels[i]);
ASSERT0(dn->dn_next_indblkshift[i]);
ASSERT0(dn->dn_next_bonustype[i]);
ASSERT0(dn->dn_rm_spillblk[i]);
ASSERT0(dn->dn_next_bonuslen[i]);
ASSERT0(dn->dn_next_blksz[i]);
}
ASSERT0(dn->dn_allocated_txg);
ASSERT0(dn->dn_free_txg);
ASSERT0(dn->dn_assigned_txg);
ASSERT0(dn->dn_dirtyctx);
ASSERT3P(dn->dn_dirtyctx_firstset, ==, NULL);
ASSERT3P(dn->dn_bonus, ==, NULL);
ASSERT(!dn->dn_have_spill);
ASSERT3P(dn->dn_zio, ==, NULL);
ASSERT0(dn->dn_oldused);
ASSERT0(dn->dn_oldflags);
ASSERT0(dn->dn_olduid);
ASSERT0(dn->dn_oldgid);
ASSERT0(dn->dn_newuid);
ASSERT0(dn->dn_newgid);
ASSERT0(dn->dn_id_flags);
ASSERT0(dn->dn_dbufs_count);
avl_destroy(&dn->dn_dbufs);
}
void
dnode_init(void)
{
ASSERT(dnode_cache == NULL);
dnode_cache = kmem_cache_create("dnode_t", sizeof (dnode_t),
0, dnode_cons, dnode_dest, NULL, NULL, NULL, 0);
kmem_cache_set_move(dnode_cache, dnode_move);
}
void
dnode_fini(void)
{
kmem_cache_destroy(dnode_cache);
dnode_cache = NULL;
}
#ifdef ZFS_DEBUG
void
dnode_verify(dnode_t *dn)
{
int drop_struct_lock = FALSE;
ASSERT(dn->dn_phys);
ASSERT(dn->dn_objset);
ASSERT(dn->dn_handle->dnh_dnode == dn);
ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type));
if (!(zfs_flags & ZFS_DEBUG_DNODE_VERIFY))
return;
if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
rw_enter(&dn->dn_struct_rwlock, RW_READER);
drop_struct_lock = TRUE;
}
if (dn->dn_phys->dn_type != DMU_OT_NONE || dn->dn_allocated_txg != 0) {
int i;
int max_bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots);
ASSERT3U(dn->dn_indblkshift, <=, SPA_MAXBLOCKSHIFT);
if (dn->dn_datablkshift) {
ASSERT3U(dn->dn_datablkshift, >=, SPA_MINBLOCKSHIFT);
ASSERT3U(dn->dn_datablkshift, <=, SPA_MAXBLOCKSHIFT);
ASSERT3U(1<<dn->dn_datablkshift, ==, dn->dn_datablksz);
}
ASSERT3U(dn->dn_nlevels, <=, 30);
ASSERT(DMU_OT_IS_VALID(dn->dn_type));
ASSERT3U(dn->dn_nblkptr, >=, 1);
ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
ASSERT3U(dn->dn_bonuslen, <=, max_bonuslen);
ASSERT3U(dn->dn_datablksz, ==,
dn->dn_datablkszsec << SPA_MINBLOCKSHIFT);
ASSERT3U(ISP2(dn->dn_datablksz), ==, dn->dn_datablkshift != 0);
ASSERT3U((dn->dn_nblkptr - 1) * sizeof (blkptr_t) +
dn->dn_bonuslen, <=, max_bonuslen);
for (i = 0; i < TXG_SIZE; i++) {
ASSERT3U(dn->dn_next_nlevels[i], <=, dn->dn_nlevels);
}
}
if (dn->dn_phys->dn_type != DMU_OT_NONE)
ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels);
ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL);
if (dn->dn_dbuf != NULL) {
ASSERT3P(dn->dn_phys, ==,
(dnode_phys_t *)dn->dn_dbuf->db.db_data +
(dn->dn_object % (dn->dn_dbuf->db.db_size >> DNODE_SHIFT)));
}
if (drop_struct_lock)
rw_exit(&dn->dn_struct_rwlock);
}
#endif
void
dnode_byteswap(dnode_phys_t *dnp)
{
uint64_t *buf64 = (void*)&dnp->dn_blkptr;
int i;
if (dnp->dn_type == DMU_OT_NONE) {
bzero(dnp, sizeof (dnode_phys_t));
return;
}
dnp->dn_datablkszsec = BSWAP_16(dnp->dn_datablkszsec);
dnp->dn_bonuslen = BSWAP_16(dnp->dn_bonuslen);
dnp->dn_extra_slots = BSWAP_8(dnp->dn_extra_slots);
dnp->dn_maxblkid = BSWAP_64(dnp->dn_maxblkid);
dnp->dn_used = BSWAP_64(dnp->dn_used);
/*
* dn_nblkptr is only one byte, so it's OK to read it in either
* byte order. We can't read dn_bouslen.
*/
ASSERT(dnp->dn_indblkshift <= SPA_MAXBLOCKSHIFT);
ASSERT(dnp->dn_nblkptr <= DN_MAX_NBLKPTR);
for (i = 0; i < dnp->dn_nblkptr * sizeof (blkptr_t)/8; i++)
buf64[i] = BSWAP_64(buf64[i]);
/*
* OK to check dn_bonuslen for zero, because it won't matter if
* we have the wrong byte order. This is necessary because the
* dnode dnode is smaller than a regular dnode.
*/
if (dnp->dn_bonuslen != 0) {
/*
* Note that the bonus length calculated here may be
* longer than the actual bonus buffer. This is because
* we always put the bonus buffer after the last block
* pointer (instead of packing it against the end of the
* dnode buffer).
*/
int off = (dnp->dn_nblkptr-1) * sizeof (blkptr_t);
int slots = dnp->dn_extra_slots + 1;
size_t len = DN_SLOTS_TO_BONUSLEN(slots) - off;
dmu_object_byteswap_t byteswap;
ASSERT(DMU_OT_IS_VALID(dnp->dn_bonustype));
byteswap = DMU_OT_BYTESWAP(dnp->dn_bonustype);
dmu_ot_byteswap[byteswap].ob_func(dnp->dn_bonus + off, len);
}
/* Swap SPILL block if we have one */
if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)
byteswap_uint64_array(DN_SPILL_BLKPTR(dnp), sizeof (blkptr_t));
}
void
dnode_buf_byteswap(void *vbuf, size_t size)
{
int i = 0;
ASSERT3U(sizeof (dnode_phys_t), ==, (1<<DNODE_SHIFT));
ASSERT((size & (sizeof (dnode_phys_t)-1)) == 0);
while (i < size) {
dnode_phys_t *dnp = vbuf + i;
dnode_byteswap(dnp);
i += DNODE_MIN_SIZE;
if (dnp->dn_type != DMU_OT_NONE)
i += dnp->dn_extra_slots * DNODE_MIN_SIZE;
}
}
void
dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx)
{
ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
dnode_setdirty(dn, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
ASSERT3U(newsize, <=, DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) -
(dn->dn_nblkptr-1) * sizeof (blkptr_t));
dn->dn_bonuslen = newsize;
if (newsize == 0)
dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN;
else
dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
rw_exit(&dn->dn_struct_rwlock);
}
void
dnode_setbonus_type(dnode_t *dn, dmu_object_type_t newtype, dmu_tx_t *tx)
{
ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
dnode_setdirty(dn, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
dn->dn_bonustype = newtype;
dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype;
rw_exit(&dn->dn_struct_rwlock);
}
void
dnode_rm_spill(dnode_t *dn, dmu_tx_t *tx)
{
ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
dnode_setdirty(dn, tx);
dn->dn_rm_spillblk[tx->tx_txg&TXG_MASK] = DN_KILL_SPILLBLK;
dn->dn_have_spill = B_FALSE;
}
static void
dnode_setdblksz(dnode_t *dn, int size)
{
ASSERT0(P2PHASE(size, SPA_MINBLOCKSIZE));
ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
ASSERT3U(size, >=, SPA_MINBLOCKSIZE);
ASSERT3U(size >> SPA_MINBLOCKSHIFT, <,
1<<(sizeof (dn->dn_phys->dn_datablkszsec) * 8));
dn->dn_datablksz = size;
dn->dn_datablkszsec = size >> SPA_MINBLOCKSHIFT;
dn->dn_datablkshift = ISP2(size) ? highbit64(size - 1) : 0;
}
static dnode_t *
dnode_create(objset_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db,
uint64_t object, dnode_handle_t *dnh)
{
dnode_t *dn;
dn = kmem_cache_alloc(dnode_cache, KM_SLEEP);
ASSERT(!POINTER_IS_VALID(dn->dn_objset));
dn->dn_moved = 0;
/*
* Defer setting dn_objset until the dnode is ready to be a candidate
* for the dnode_move() callback.
*/
dn->dn_object = object;
dn->dn_dbuf = db;
dn->dn_handle = dnh;
dn->dn_phys = dnp;
if (dnp->dn_datablkszsec) {
dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
} else {
dn->dn_datablksz = 0;
dn->dn_datablkszsec = 0;
dn->dn_datablkshift = 0;
}
dn->dn_indblkshift = dnp->dn_indblkshift;
dn->dn_nlevels = dnp->dn_nlevels;
dn->dn_type = dnp->dn_type;
dn->dn_nblkptr = dnp->dn_nblkptr;
dn->dn_checksum = dnp->dn_checksum;
dn->dn_compress = dnp->dn_compress;
dn->dn_bonustype = dnp->dn_bonustype;
dn->dn_bonuslen = dnp->dn_bonuslen;
dn->dn_num_slots = dnp->dn_extra_slots + 1;
dn->dn_maxblkid = dnp->dn_maxblkid;
dn->dn_have_spill = ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0);
dn->dn_id_flags = 0;
dmu_zfetch_init(&dn->dn_zfetch, dn);
ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type));
mutex_enter(&os->os_lock);
if (dnh->dnh_dnode != NULL) {
/* Lost the allocation race. */
mutex_exit(&os->os_lock);
kmem_cache_free(dnode_cache, dn);
return (dnh->dnh_dnode);
}
/*
* Exclude special dnodes from os_dnodes so an empty os_dnodes
* signifies that the special dnodes have no references from
* their children (the entries in os_dnodes). This allows
* dnode_destroy() to easily determine if the last child has
* been removed and then complete eviction of the objset.
*/
if (!DMU_OBJECT_IS_SPECIAL(object))
list_insert_head(&os->os_dnodes, dn);
membar_producer();
/*
* Everything else must be valid before assigning dn_objset
* makes the dnode eligible for dnode_move().
*/
dn->dn_objset = os;
dnh->dnh_dnode = dn;
mutex_exit(&os->os_lock);
arc_space_consume(sizeof (dnode_t), ARC_SPACE_DNODE);
return (dn);
}
/*
* Caller must be holding the dnode handle, which is released upon return.
*/
static void
dnode_destroy(dnode_t *dn)
{
objset_t *os = dn->dn_objset;
boolean_t complete_os_eviction = B_FALSE;
ASSERT((dn->dn_id_flags & DN_ID_NEW_EXIST) == 0);
mutex_enter(&os->os_lock);
POINTER_INVALIDATE(&dn->dn_objset);
if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
list_remove(&os->os_dnodes, dn);
complete_os_eviction =
list_is_empty(&os->os_dnodes) &&
list_link_active(&os->os_evicting_node);
}
mutex_exit(&os->os_lock);
/* the dnode can no longer move, so we can release the handle */
zrl_remove(&dn->dn_handle->dnh_zrlock);
dn->dn_allocated_txg = 0;
dn->dn_free_txg = 0;
dn->dn_assigned_txg = 0;
dn->dn_dirtyctx = 0;
if (dn->dn_dirtyctx_firstset != NULL) {
kmem_free(dn->dn_dirtyctx_firstset, 1);
dn->dn_dirtyctx_firstset = NULL;
}
if (dn->dn_bonus != NULL) {
mutex_enter(&dn->dn_bonus->db_mtx);
dbuf_destroy(dn->dn_bonus);
dn->dn_bonus = NULL;
}
dn->dn_zio = NULL;
dn->dn_have_spill = B_FALSE;
dn->dn_oldused = 0;
dn->dn_oldflags = 0;
dn->dn_olduid = 0;
dn->dn_oldgid = 0;
dn->dn_newuid = 0;
dn->dn_newgid = 0;
dn->dn_id_flags = 0;
dmu_zfetch_fini(&dn->dn_zfetch);
kmem_cache_free(dnode_cache, dn);
arc_space_return(sizeof (dnode_t), ARC_SPACE_DNODE);
if (complete_os_eviction)
dmu_objset_evict_done(os);
}
void
dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx)
{
int i;
ASSERT3U(dn_slots, >, 0);
ASSERT3U(dn_slots << DNODE_SHIFT, <=,
spa_maxdnodesize(dmu_objset_spa(dn->dn_objset)));
ASSERT3U(blocksize, <=,
spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
if (blocksize == 0)
blocksize = 1 << zfs_default_bs;
else
blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE);
if (ibs == 0)
ibs = zfs_default_ibs;
ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT);
dprintf("os=%p obj=%llu txg=%llu blocksize=%d ibs=%d dn_slots=%d\n",
dn->dn_objset, dn->dn_object, tx->tx_txg, blocksize, ibs, dn_slots);
ASSERT(dn->dn_type == DMU_OT_NONE);
ASSERT(bcmp(dn->dn_phys, &dnode_phys_zero, sizeof (dnode_phys_t)) == 0);
ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE);
ASSERT(ot != DMU_OT_NONE);
ASSERT(DMU_OT_IS_VALID(ot));
ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) ||
(bonustype == DMU_OT_SA && bonuslen == 0) ||
(bonustype != DMU_OT_NONE && bonuslen != 0));
ASSERT(DMU_OT_IS_VALID(bonustype));
ASSERT3U(bonuslen, <=, DN_SLOTS_TO_BONUSLEN(dn_slots));
ASSERT(dn->dn_type == DMU_OT_NONE);
ASSERT0(dn->dn_maxblkid);
ASSERT0(dn->dn_allocated_txg);
ASSERT0(dn->dn_assigned_txg);
ASSERT(refcount_is_zero(&dn->dn_tx_holds));
ASSERT3U(refcount_count(&dn->dn_holds), <=, 1);
ASSERT(avl_is_empty(&dn->dn_dbufs));
for (i = 0; i < TXG_SIZE; i++) {
ASSERT0(dn->dn_next_nblkptr[i]);
ASSERT0(dn->dn_next_nlevels[i]);
ASSERT0(dn->dn_next_indblkshift[i]);
ASSERT0(dn->dn_next_bonuslen[i]);
ASSERT0(dn->dn_next_bonustype[i]);
ASSERT0(dn->dn_rm_spillblk[i]);
ASSERT0(dn->dn_next_blksz[i]);
ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL);
ASSERT3P(dn->dn_free_ranges[i], ==, NULL);
}
dn->dn_type = ot;
dnode_setdblksz(dn, blocksize);
dn->dn_indblkshift = ibs;
dn->dn_nlevels = 1;
dn->dn_num_slots = dn_slots;
if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */
dn->dn_nblkptr = 1;
else {
dn->dn_nblkptr = MIN(DN_MAX_NBLKPTR,
1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >>
SPA_BLKPTRSHIFT));
}
dn->dn_bonustype = bonustype;
dn->dn_bonuslen = bonuslen;
dn->dn_checksum = ZIO_CHECKSUM_INHERIT;
dn->dn_compress = ZIO_COMPRESS_INHERIT;
dn->dn_dirtyctx = 0;
dn->dn_free_txg = 0;
if (dn->dn_dirtyctx_firstset) {
kmem_free(dn->dn_dirtyctx_firstset, 1);
dn->dn_dirtyctx_firstset = NULL;
}
dn->dn_allocated_txg = tx->tx_txg;
dn->dn_id_flags = 0;
dnode_setdirty(dn, tx);
dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs;
dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype;
dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz;
}
void
dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx)
{
int nblkptr;
ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE);
ASSERT3U(blocksize, <=,
spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
ASSERT0(blocksize % SPA_MINBLOCKSIZE);
ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx));
ASSERT(tx->tx_txg != 0);
ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) ||
(bonustype != DMU_OT_NONE && bonuslen != 0) ||
(bonustype == DMU_OT_SA && bonuslen == 0));
ASSERT(DMU_OT_IS_VALID(bonustype));
ASSERT3U(bonuslen, <=,
DN_BONUS_SIZE(spa_maxdnodesize(dmu_objset_spa(dn->dn_objset))));
dn_slots = dn_slots > 0 ? dn_slots : DNODE_MIN_SLOTS;
/* clean up any unreferenced dbufs */
dnode_evict_dbufs(dn);
dn->dn_id_flags = 0;
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
dnode_setdirty(dn, tx);
if (dn->dn_datablksz != blocksize) {
/* change blocksize */
ASSERT(dn->dn_maxblkid == 0 &&
(BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) ||
dnode_block_freed(dn, 0)));
dnode_setdblksz(dn, blocksize);
dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize;
}
if (dn->dn_bonuslen != bonuslen)
dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen;
if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */
nblkptr = 1;
else
nblkptr = MIN(DN_MAX_NBLKPTR,
1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >>
SPA_BLKPTRSHIFT));
if (dn->dn_bonustype != bonustype)
dn->dn_next_bonustype[tx->tx_txg&TXG_MASK] = bonustype;
if (dn->dn_nblkptr != nblkptr)
dn->dn_next_nblkptr[tx->tx_txg&TXG_MASK] = nblkptr;
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);
/* change type */
dn->dn_type = ot;
/* change bonus size and type */
mutex_enter(&dn->dn_mtx);
dn->dn_bonustype = bonustype;
dn->dn_bonuslen = bonuslen;
dn->dn_num_slots = dn_slots;
dn->dn_nblkptr = nblkptr;
dn->dn_checksum = ZIO_CHECKSUM_INHERIT;
dn->dn_compress = ZIO_COMPRESS_INHERIT;
ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
/* fix up the bonus db_size */
if (dn->dn_bonus) {
dn->dn_bonus->db.db_size =
DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) -
(dn->dn_nblkptr-1) * sizeof (blkptr_t);
ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size);
}
dn->dn_allocated_txg = tx->tx_txg;
mutex_exit(&dn->dn_mtx);
}
#ifdef _KERNEL
#ifdef DNODE_STATS
static struct {
uint64_t dms_dnode_invalid;
uint64_t dms_dnode_recheck1;
uint64_t dms_dnode_recheck2;
uint64_t dms_dnode_special;
uint64_t dms_dnode_handle;
uint64_t dms_dnode_rwlock;
uint64_t dms_dnode_active;
} dnode_move_stats;
#endif /* DNODE_STATS */
static void
dnode_move_impl(dnode_t *odn, dnode_t *ndn)
{
int i;
ASSERT(!RW_LOCK_HELD(&odn->dn_struct_rwlock));
ASSERT(MUTEX_NOT_HELD(&odn->dn_mtx));
ASSERT(MUTEX_NOT_HELD(&odn->dn_dbufs_mtx));
ASSERT(!RW_LOCK_HELD(&odn->dn_zfetch.zf_rwlock));
/* Copy fields. */
ndn->dn_objset = odn->dn_objset;
ndn->dn_object = odn->dn_object;
ndn->dn_dbuf = odn->dn_dbuf;
ndn->dn_handle = odn->dn_handle;
ndn->dn_phys = odn->dn_phys;
ndn->dn_type = odn->dn_type;
ndn->dn_bonuslen = odn->dn_bonuslen;
ndn->dn_bonustype = odn->dn_bonustype;
ndn->dn_nblkptr = odn->dn_nblkptr;
ndn->dn_checksum = odn->dn_checksum;
ndn->dn_compress = odn->dn_compress;
ndn->dn_nlevels = odn->dn_nlevels;
ndn->dn_indblkshift = odn->dn_indblkshift;
ndn->dn_datablkshift = odn->dn_datablkshift;
ndn->dn_datablkszsec = odn->dn_datablkszsec;
ndn->dn_datablksz = odn->dn_datablksz;
ndn->dn_maxblkid = odn->dn_maxblkid;
bcopy(&odn->dn_next_nblkptr[0], &ndn->dn_next_nblkptr[0],
sizeof (odn->dn_next_nblkptr));
bcopy(&odn->dn_next_nlevels[0], &ndn->dn_next_nlevels[0],
sizeof (odn->dn_next_nlevels));
bcopy(&odn->dn_next_indblkshift[0], &ndn->dn_next_indblkshift[0],
sizeof (odn->dn_next_indblkshift));
bcopy(&odn->dn_next_bonustype[0], &ndn->dn_next_bonustype[0],
sizeof (odn->dn_next_bonustype));
bcopy(&odn->dn_rm_spillblk[0], &ndn->dn_rm_spillblk[0],
sizeof (odn->dn_rm_spillblk));
bcopy(&odn->dn_next_bonuslen[0], &ndn->dn_next_bonuslen[0],
sizeof (odn->dn_next_bonuslen));
bcopy(&odn->dn_next_blksz[0], &ndn->dn_next_blksz[0],
sizeof (odn->dn_next_blksz));
for (i = 0; i < TXG_SIZE; i++) {
list_move_tail(&ndn->dn_dirty_records[i],
&odn->dn_dirty_records[i]);
}
bcopy(&odn->dn_free_ranges[0], &ndn->dn_free_ranges[0],
sizeof (odn->dn_free_ranges));
ndn->dn_allocated_txg = odn->dn_allocated_txg;
ndn->dn_free_txg = odn->dn_free_txg;
ndn->dn_assigned_txg = odn->dn_assigned_txg;
ndn->dn_dirtyctx = odn->dn_dirtyctx;
ndn->dn_dirtyctx_firstset = odn->dn_dirtyctx_firstset;
ASSERT(refcount_count(&odn->dn_tx_holds) == 0);
refcount_transfer(&ndn->dn_holds, &odn->dn_holds);
ASSERT(avl_is_empty(&ndn->dn_dbufs));
avl_swap(&ndn->dn_dbufs, &odn->dn_dbufs);
ndn->dn_dbufs_count = odn->dn_dbufs_count;
ndn->dn_bonus = odn->dn_bonus;
ndn->dn_have_spill = odn->dn_have_spill;
ndn->dn_zio = odn->dn_zio;
ndn->dn_oldused = odn->dn_oldused;
ndn->dn_oldflags = odn->dn_oldflags;
ndn->dn_olduid = odn->dn_olduid;
ndn->dn_oldgid = odn->dn_oldgid;
ndn->dn_newuid = odn->dn_newuid;
ndn->dn_newgid = odn->dn_newgid;
ndn->dn_id_flags = odn->dn_id_flags;
dmu_zfetch_init(&ndn->dn_zfetch, NULL);
list_move_tail(&ndn->dn_zfetch.zf_stream, &odn->dn_zfetch.zf_stream);
ndn->dn_zfetch.zf_dnode = odn->dn_zfetch.zf_dnode;
/*
* Update back pointers. Updating the handle fixes the back pointer of
* every descendant dbuf as well as the bonus dbuf.
*/
ASSERT(ndn->dn_handle->dnh_dnode == odn);
ndn->dn_handle->dnh_dnode = ndn;
if (ndn->dn_zfetch.zf_dnode == odn) {
ndn->dn_zfetch.zf_dnode = ndn;
}
/*
* Invalidate the original dnode by clearing all of its back pointers.
*/
odn->dn_dbuf = NULL;
odn->dn_handle = NULL;
avl_create(&odn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t),
offsetof(dmu_buf_impl_t, db_link));
odn->dn_dbufs_count = 0;
odn->dn_bonus = NULL;
odn->dn_zfetch.zf_dnode = NULL;
/*
* Set the low bit of the objset pointer to ensure that dnode_move()
* recognizes the dnode as invalid in any subsequent callback.
*/
POINTER_INVALIDATE(&odn->dn_objset);
/*
* Satisfy the destructor.
*/
for (i = 0; i < TXG_SIZE; i++) {
list_create(&odn->dn_dirty_records[i],
sizeof (dbuf_dirty_record_t),
offsetof(dbuf_dirty_record_t, dr_dirty_node));
odn->dn_free_ranges[i] = NULL;
odn->dn_next_nlevels[i] = 0;
odn->dn_next_indblkshift[i] = 0;
odn->dn_next_bonustype[i] = 0;
odn->dn_rm_spillblk[i] = 0;
odn->dn_next_bonuslen[i] = 0;
odn->dn_next_blksz[i] = 0;
}
odn->dn_allocated_txg = 0;
odn->dn_free_txg = 0;
odn->dn_assigned_txg = 0;
odn->dn_dirtyctx = 0;
odn->dn_dirtyctx_firstset = NULL;
odn->dn_have_spill = B_FALSE;
odn->dn_zio = NULL;
odn->dn_oldused = 0;
odn->dn_oldflags = 0;
odn->dn_olduid = 0;
odn->dn_oldgid = 0;
odn->dn_newuid = 0;
odn->dn_newgid = 0;
odn->dn_id_flags = 0;
/*
* Mark the dnode.
*/
ndn->dn_moved = 1;
odn->dn_moved = (uint8_t)-1;
}
/*ARGSUSED*/
static kmem_cbrc_t
dnode_move(void *buf, void *newbuf, size_t size, void *arg)
{
dnode_t *odn = buf, *ndn = newbuf;
objset_t *os;
int64_t refcount;
uint32_t dbufs;
/*
* The dnode is on the objset's list of known dnodes if the objset
* pointer is valid. We set the low bit of the objset pointer when
* freeing the dnode to invalidate it, and the memory patterns written
* by kmem (baddcafe and deadbeef) set at least one of the two low bits.
* A newly created dnode sets the objset pointer last of all to indicate
* that the dnode is known and in a valid state to be moved by this
* function.
*/
os = odn->dn_objset;
if (!POINTER_IS_VALID(os)) {
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_invalid);
return (KMEM_CBRC_DONT_KNOW);
}
/*
* Ensure that the objset does not go away during the move.
*/
rw_enter(&os_lock, RW_WRITER);
if (os != odn->dn_objset) {
rw_exit(&os_lock);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_recheck1);
return (KMEM_CBRC_DONT_KNOW);
}
/*
* If the dnode is still valid, then so is the objset. We know that no
* valid objset can be freed while we hold os_lock, so we can safely
* ensure that the objset remains in use.
*/
mutex_enter(&os->os_lock);
/*
* Recheck the objset pointer in case the dnode was removed just before
* acquiring the lock.
*/
if (os != odn->dn_objset) {
mutex_exit(&os->os_lock);
rw_exit(&os_lock);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_recheck2);
return (KMEM_CBRC_DONT_KNOW);
}
/*
* At this point we know that as long as we hold os->os_lock, the dnode
* cannot be freed and fields within the dnode can be safely accessed.
* The objset listing this dnode cannot go away as long as this dnode is
* on its list.
*/
rw_exit(&os_lock);
if (DMU_OBJECT_IS_SPECIAL(odn->dn_object)) {
mutex_exit(&os->os_lock);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_special);
return (KMEM_CBRC_NO);
}
ASSERT(odn->dn_dbuf != NULL); /* only "special" dnodes have no parent */
/*
* Lock the dnode handle to prevent the dnode from obtaining any new
* holds. This also prevents the descendant dbufs and the bonus dbuf
* from accessing the dnode, so that we can discount their holds. The
* handle is safe to access because we know that while the dnode cannot
* go away, neither can its handle. Once we hold dnh_zrlock, we can
* safely move any dnode referenced only by dbufs.
*/
if (!zrl_tryenter(&odn->dn_handle->dnh_zrlock)) {
mutex_exit(&os->os_lock);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_handle);
return (KMEM_CBRC_LATER);
}
/*
* Ensure a consistent view of the dnode's holds and the dnode's dbufs.
* We need to guarantee that there is a hold for every dbuf in order to
* determine whether the dnode is actively referenced. Falsely matching
* a dbuf to an active hold would lead to an unsafe move. It's possible
* that a thread already having an active dnode hold is about to add a
* dbuf, and we can't compare hold and dbuf counts while the add is in
* progress.
*/
if (!rw_tryenter(&odn->dn_struct_rwlock, RW_WRITER)) {
zrl_exit(&odn->dn_handle->dnh_zrlock);
mutex_exit(&os->os_lock);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_rwlock);
return (KMEM_CBRC_LATER);
}
/*
* A dbuf may be removed (evicted) without an active dnode hold. In that
* case, the dbuf count is decremented under the handle lock before the
* dbuf's hold is released. This order ensures that if we count the hold
* after the dbuf is removed but before its hold is released, we will
* treat the unmatched hold as active and exit safely. If we count the
* hold before the dbuf is removed, the hold is discounted, and the
* removal is blocked until the move completes.
*/
refcount = refcount_count(&odn->dn_holds);
ASSERT(refcount >= 0);
dbufs = odn->dn_dbufs_count;
/* We can't have more dbufs than dnode holds. */
ASSERT3U(dbufs, <=, refcount);
DTRACE_PROBE3(dnode__move, dnode_t *, odn, int64_t, refcount,
uint32_t, dbufs);
if (refcount > dbufs) {
rw_exit(&odn->dn_struct_rwlock);
zrl_exit(&odn->dn_handle->dnh_zrlock);
mutex_exit(&os->os_lock);
DNODE_STAT_ADD(dnode_move_stats.dms_dnode_active);
return (KMEM_CBRC_LATER);
}
rw_exit(&odn->dn_struct_rwlock);
/*
* At this point we know that anyone with a hold on the dnode is not
* actively referencing it. The dnode is known and in a valid state to
* move. We're holding the locks needed to execute the critical section.
*/
dnode_move_impl(odn, ndn);
list_link_replace(&odn->dn_link, &ndn->dn_link);
/* If the dnode was safe to move, the refcount cannot have changed. */
ASSERT(refcount == refcount_count(&ndn->dn_holds));
ASSERT(dbufs == ndn->dn_dbufs_count);
zrl_exit(&ndn->dn_handle->dnh_zrlock); /* handle has moved */
mutex_exit(&os->os_lock);
return (KMEM_CBRC_YES);
}
#endif /* _KERNEL */
void
dnode_special_close(dnode_handle_t *dnh)
{
dnode_t *dn = dnh->dnh_dnode;
/*
* Wait for final references to the dnode to clear. This can
* only happen if the arc is asyncronously evicting state that
* has a hold on this dnode while we are trying to evict this
* dnode.
*/
while (refcount_count(&dn->dn_holds) > 0)
delay(1);
ASSERT(dn->dn_dbuf == NULL ||
dmu_buf_get_user(&dn->dn_dbuf->db) == NULL);
zrl_add(&dnh->dnh_zrlock);
dnode_destroy(dn); /* implicit zrl_remove() */
zrl_destroy(&dnh->dnh_zrlock);
dnh->dnh_dnode = NULL;
}
void
dnode_special_open(objset_t *os, dnode_phys_t *dnp, uint64_t object,
dnode_handle_t *dnh)
{
dnode_t *dn;
dn = dnode_create(os, dnp, NULL, object, dnh);
zrl_init(&dnh->dnh_zrlock);
DNODE_VERIFY(dn);
}
static void
dnode_buf_evict_async(void *dbu)
{
dnode_children_t *children_dnodes = dbu;
int i;
for (i = 0; i < children_dnodes->dnc_count; i++) {
dnode_handle_t *dnh = &children_dnodes->dnc_children[i];
dnode_t *dn;
/*
* The dnode handle lock guards against the dnode moving to
* another valid address, so there is no need here to guard
* against changes to or from NULL.
*/
if (dnh->dnh_dnode == NULL) {
zrl_destroy(&dnh->dnh_zrlock);
continue;
}
zrl_add(&dnh->dnh_zrlock);
dn = dnh->dnh_dnode;
/*
* If there are holds on this dnode, then there should
* be holds on the dnode's containing dbuf as well; thus
* it wouldn't be eligible for eviction and this function
* would not have been called.
*/
ASSERT(refcount_is_zero(&dn->dn_holds));
ASSERT(refcount_is_zero(&dn->dn_tx_holds));
dnode_destroy(dn); /* implicit zrl_remove() */
zrl_destroy(&dnh->dnh_zrlock);
dnh->dnh_dnode = NULL;
}
kmem_free(children_dnodes, sizeof (dnode_children_t) +
children_dnodes->dnc_count * sizeof (dnode_handle_t));
}
/*
* Return true if the given index is interior to a dnode already
* allocated in the block. That is, the index is neither free nor
* allocated, but is consumed by a large dnode.
*
* The dnode_phys_t buffer may not be in sync with the in-core dnode
* structure, so we try to check the dnode structure first and fall back
* to the dnode_phys_t buffer it doesn't exist.
*/
static boolean_t
dnode_is_consumed(dmu_buf_impl_t *db, int idx)
{
dnode_handle_t *dnh;
dmu_object_type_t ot;
dnode_children_t *children_dnodes;
dnode_phys_t *dn_block;
int skip;
int i;
children_dnodes = dmu_buf_get_user(&db->db);
dn_block = (dnode_phys_t *)db->db.db_data;
for (i = 0; i < idx; i += skip) {
dnh = &children_dnodes->dnc_children[i];
zrl_add(&dnh->dnh_zrlock);
if (dnh->dnh_dnode != NULL) {
ot = dnh->dnh_dnode->dn_type;
skip = dnh->dnh_dnode->dn_num_slots;
} else {
ot = dn_block[i].dn_type;
skip = dn_block[i].dn_extra_slots + 1;
}
zrl_remove(&dnh->dnh_zrlock);
if (ot == DMU_OT_NONE)
skip = 1;
}
return (i > idx);
}
/*
* Return true if the given index in the dnode block is a valid
* allocated dnode. That is, the index is not consumed by a large
* dnode and is not free.
*
* The dnode_phys_t buffer may not be in sync with the in-core dnode
* structure, so we try to check the dnode structure first and fall back
* to the dnode_phys_t buffer it doesn't exist.
*/
static boolean_t
dnode_is_allocated(dmu_buf_impl_t *db, int idx)
{
dnode_handle_t *dnh;
dmu_object_type_t ot;
dnode_children_t *children_dnodes;
dnode_phys_t *dn_block;
if (dnode_is_consumed(db, idx))
return (B_FALSE);
children_dnodes = dmu_buf_get_user(&db->db);
dn_block = (dnode_phys_t *)db->db.db_data;
dnh = &children_dnodes->dnc_children[idx];
zrl_add(&dnh->dnh_zrlock);
if (dnh->dnh_dnode != NULL)
ot = dnh->dnh_dnode->dn_type;
else
ot = dn_block[idx].dn_type;
zrl_remove(&dnh->dnh_zrlock);
return (ot != DMU_OT_NONE);
}
/*
* Return true if the given range of indices in the dnode block are
* free. That is, the starting index is not consumed by a large dnode
* and none of the indices are allocated.
*
* The dnode_phys_t buffer may not be in sync with the in-core dnode
* structure, so we try to check the dnode structure first and fall back
* to the dnode_phys_t buffer it doesn't exist.
*/
static boolean_t
dnode_is_free(dmu_buf_impl_t *db, int idx, int slots)
{
dnode_handle_t *dnh;
dmu_object_type_t ot;
dnode_children_t *children_dnodes;
dnode_phys_t *dn_block;
int i;
if (idx + slots > DNODES_PER_BLOCK)
return (B_FALSE);
children_dnodes = dmu_buf_get_user(&db->db);
dn_block = (dnode_phys_t *)db->db.db_data;
if (dnode_is_consumed(db, idx))
return (B_FALSE);
for (i = idx; i < idx + slots; i++) {
dnh = &children_dnodes->dnc_children[i];
zrl_add(&dnh->dnh_zrlock);
if (dnh->dnh_dnode != NULL)
ot = dnh->dnh_dnode->dn_type;
else
ot = dn_block[i].dn_type;
zrl_remove(&dnh->dnh_zrlock);
if (ot != DMU_OT_NONE)
return (B_FALSE);
}
return (B_TRUE);
}
/*
* errors:
* EINVAL - invalid object number.
* ENOSPC - hole too small to fulfill "slots" request
* ENOENT - the requested dnode is not allocated
* EIO - i/o error.
* succeeds even for free dnodes.
*/
int
dnode_hold_impl(objset_t *os, uint64_t object, int flag, int slots,
void *tag, dnode_t **dnp)
{
int epb, idx, err, i;
int drop_struct_lock = FALSE;
int type;
uint64_t blk;
dnode_t *mdn, *dn;
dmu_buf_impl_t *db;
dnode_children_t *children_dnodes;
dnode_phys_t *dn_block_begin;
dnode_handle_t *dnh;
ASSERT(!(flag & DNODE_MUST_BE_ALLOCATED) || (slots == 0));
ASSERT(!(flag & DNODE_MUST_BE_FREE) || (slots > 0));
/*
* If you are holding the spa config lock as writer, you shouldn't
* be asking the DMU to do *anything* unless it's the root pool
* which may require us to read from the root filesystem while
* holding some (not all) of the locks as writer.
*/
ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0 ||
(spa_is_root(os->os_spa) &&
spa_config_held(os->os_spa, SCL_STATE, RW_WRITER)));
if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT) {
dn = (object == DMU_USERUSED_OBJECT) ?
DMU_USERUSED_DNODE(os) : DMU_GROUPUSED_DNODE(os);
if (dn == NULL)
return (SET_ERROR(ENOENT));
type = dn->dn_type;
if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE)
return (SET_ERROR(ENOENT));
if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE)
return (SET_ERROR(EEXIST));
DNODE_VERIFY(dn);
(void) refcount_add(&dn->dn_holds, tag);
*dnp = dn;
return (0);
}
if (object == 0 || object >= DN_MAX_OBJECT)
return (SET_ERROR(EINVAL));
mdn = DMU_META_DNODE(os);
ASSERT(mdn->dn_object == DMU_META_DNODE_OBJECT);
DNODE_VERIFY(mdn);
if (!RW_WRITE_HELD(&mdn->dn_struct_rwlock)) {
rw_enter(&mdn->dn_struct_rwlock, RW_READER);
drop_struct_lock = TRUE;
}
blk = dbuf_whichblock(mdn, 0, object * sizeof (dnode_phys_t));
db = dbuf_hold(mdn, blk, FTAG);
if (drop_struct_lock)
rw_exit(&mdn->dn_struct_rwlock);
if (db == NULL)
return (SET_ERROR(EIO));
err = dbuf_read(db, NULL, DB_RF_CANFAIL);
if (err) {
dbuf_rele(db, FTAG);
return (err);
}
ASSERT3U(db->db.db_size, >=, 1<<DNODE_SHIFT);
epb = db->db.db_size >> DNODE_SHIFT;
ASSERT(DB_DNODE(db)->dn_type == DMU_OT_DNODE);
children_dnodes = dmu_buf_get_user(&db->db);
if (children_dnodes == NULL) {
dnode_children_t *winner;
children_dnodes = kmem_zalloc(sizeof (dnode_children_t) +
epb * sizeof (dnode_handle_t), KM_SLEEP);
children_dnodes->dnc_count = epb;
dnh = &children_dnodes->dnc_children[0];
for (i = 0; i < epb; i++) {
zrl_init(&dnh[i].dnh_zrlock);
}
dmu_buf_init_user(&children_dnodes->dnc_dbu, NULL,
dnode_buf_evict_async, NULL);
winner = dmu_buf_set_user(&db->db, &children_dnodes->dnc_dbu);
if (winner != NULL) {
for (i = 0; i < epb; i++) {
zrl_destroy(&dnh[i].dnh_zrlock);
}
kmem_free(children_dnodes, sizeof (dnode_children_t) +
epb * sizeof (dnode_handle_t));
children_dnodes = winner;
}
}
ASSERT(children_dnodes->dnc_count == epb);
idx = object & (epb - 1);
dn_block_begin = (dnode_phys_t *)db->db.db_data;
if ((flag & DNODE_MUST_BE_FREE) && !dnode_is_free(db, idx, slots)) {
dbuf_rele(db, FTAG);
return (ENOSPC);
} else if ((flag & DNODE_MUST_BE_ALLOCATED) &&
!dnode_is_allocated(db, idx)) {
dbuf_rele(db, FTAG);
return (ENOENT);
}
dnh = &children_dnodes->dnc_children[idx];
zrl_add(&dnh->dnh_zrlock);
dn = dnh->dnh_dnode;
if (dn == NULL)
dn = dnode_create(os, dn_block_begin + idx, db, object, dnh);
mutex_enter(&dn->dn_mtx);
type = dn->dn_type;
if (dn->dn_free_txg ||
((flag & DNODE_MUST_BE_FREE) && !refcount_is_zero(&dn->dn_holds))) {
mutex_exit(&dn->dn_mtx);
zrl_remove(&dnh->dnh_zrlock);
dbuf_rele(db, FTAG);
return (type == DMU_OT_NONE ? ENOENT : EEXIST);
}
if (refcount_add(&dn->dn_holds, tag) == 1)
dbuf_add_ref(db, dnh);
mutex_exit(&dn->dn_mtx);
/* Now we can rely on the hold to prevent the dnode from moving. */
zrl_remove(&dnh->dnh_zrlock);
DNODE_VERIFY(dn);
ASSERT3P(dn->dn_dbuf, ==, db);
ASSERT3U(dn->dn_object, ==, object);
dbuf_rele(db, FTAG);
*dnp = dn;
return (0);
}
/*
* Return held dnode if the object is allocated, NULL if not.
*/
int
dnode_hold(objset_t *os, uint64_t object, void *tag, dnode_t **dnp)
{
return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0, tag,
dnp));
}
/*
* Can only add a reference if there is already at least one
* reference on the dnode. Returns FALSE if unable to add a
* new reference.
*/
boolean_t
dnode_add_ref(dnode_t *dn, void *tag)
{
mutex_enter(&dn->dn_mtx);
if (refcount_is_zero(&dn->dn_holds)) {
mutex_exit(&dn->dn_mtx);
return (FALSE);
}
VERIFY(1 < refcount_add(&dn->dn_holds, tag));
mutex_exit(&dn->dn_mtx);
return (TRUE);
}
void
dnode_rele(dnode_t *dn, void *tag)
{
mutex_enter(&dn->dn_mtx);
dnode_rele_and_unlock(dn, tag);
}
void
dnode_rele_and_unlock(dnode_t *dn, void *tag)
{
uint64_t refs;
/* Get while the hold prevents the dnode from moving. */
dmu_buf_impl_t *db = dn->dn_dbuf;
dnode_handle_t *dnh = dn->dn_handle;
refs = refcount_remove(&dn->dn_holds, tag);
mutex_exit(&dn->dn_mtx);
/*
* It's unsafe to release the last hold on a dnode by dnode_rele() or
* indirectly by dbuf_rele() while relying on the dnode handle to
* prevent the dnode from moving, since releasing the last hold could
* result in the dnode's parent dbuf evicting its dnode handles. For
* that reason anyone calling dnode_rele() or dbuf_rele() without some
* other direct or indirect hold on the dnode must first drop the dnode
* handle.
*/
ASSERT(refs > 0 || dnh->dnh_zrlock.zr_owner != curthread);
/* NOTE: the DNODE_DNODE does not have a dn_dbuf */
if (refs == 0 && db != NULL) {
/*
* Another thread could add a hold to the dnode handle in
* dnode_hold_impl() while holding the parent dbuf. Since the
* hold on the parent dbuf prevents the handle from being
* destroyed, the hold on the handle is OK. We can't yet assert
* that the handle has zero references, but that will be
* asserted anyway when the handle gets destroyed.
*/
dbuf_rele(db, dnh);
}
}
void
dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
{
objset_t *os = dn->dn_objset;
uint64_t txg = tx->tx_txg;
if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
dsl_dataset_dirty(os->os_dsl_dataset, tx);
return;
}
DNODE_VERIFY(dn);
#ifdef ZFS_DEBUG
mutex_enter(&dn->dn_mtx);
ASSERT(dn->dn_phys->dn_type || dn->dn_allocated_txg);
ASSERT(dn->dn_free_txg == 0 || dn->dn_free_txg >= txg);
mutex_exit(&dn->dn_mtx);
#endif
/*
* Determine old uid/gid when necessary
*/
dmu_objset_userquota_get_ids(dn, B_TRUE, tx);
mutex_enter(&os->os_lock);
/*
* If we are already marked dirty, we're done.
*/
if (list_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) {
mutex_exit(&os->os_lock);
return;
}
ASSERT(!refcount_is_zero(&dn->dn_holds) ||
!avl_is_empty(&dn->dn_dbufs));
ASSERT(dn->dn_datablksz != 0);
ASSERT0(dn->dn_next_bonuslen[txg&TXG_MASK]);
ASSERT0(dn->dn_next_blksz[txg&TXG_MASK]);
ASSERT0(dn->dn_next_bonustype[txg&TXG_MASK]);
dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n",
dn->dn_object, txg);
if (dn->dn_free_txg > 0 && dn->dn_free_txg <= txg) {
list_insert_tail(&os->os_free_dnodes[txg&TXG_MASK], dn);
} else {
list_insert_tail(&os->os_dirty_dnodes[txg&TXG_MASK], dn);
}
mutex_exit(&os->os_lock);
/*
* The dnode maintains a hold on its containing dbuf as
* long as there are holds on it. Each instantiated child
* dbuf maintains a hold on the dnode. When the last child
* drops its hold, the dnode will drop its hold on the
* containing dbuf. We add a "dirty hold" here so that the
* dnode will hang around after we finish processing its
* children.
*/
VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg));
(void) dbuf_dirty(dn->dn_dbuf, tx);
dsl_dataset_dirty(os->os_dsl_dataset, tx);
}
void
dnode_free(dnode_t *dn, dmu_tx_t *tx)
{
int txgoff = tx->tx_txg & TXG_MASK;
dprintf("dn=%p txg=%llu\n", dn, tx->tx_txg);
/* we should be the only holder... hopefully */
/* ASSERT3U(refcount_count(&dn->dn_holds), ==, 1); */
mutex_enter(&dn->dn_mtx);
if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg) {
mutex_exit(&dn->dn_mtx);
return;
}
dn->dn_free_txg = tx->tx_txg;
mutex_exit(&dn->dn_mtx);
/*
* If the dnode is already dirty, it needs to be moved from
* the dirty list to the free list.
*/
mutex_enter(&dn->dn_objset->os_lock);
if (list_link_active(&dn->dn_dirty_link[txgoff])) {
list_remove(&dn->dn_objset->os_dirty_dnodes[txgoff], dn);
list_insert_tail(&dn->dn_objset->os_free_dnodes[txgoff], dn);
mutex_exit(&dn->dn_objset->os_lock);
} else {
mutex_exit(&dn->dn_objset->os_lock);
dnode_setdirty(dn, tx);
}
}
/*
* Try to change the block size for the indicated dnode. This can only
* succeed if there are no blocks allocated or dirty beyond first block
*/
int
dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
{
dmu_buf_impl_t *db;
int err;
ASSERT3U(size, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
if (size == 0)
size = SPA_MINBLOCKSIZE;
else
size = P2ROUNDUP(size, SPA_MINBLOCKSIZE);
if (ibs == dn->dn_indblkshift)
ibs = 0;
if (size >> SPA_MINBLOCKSHIFT == dn->dn_datablkszsec && ibs == 0)
return (0);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
/* Check for any allocated blocks beyond the first */
if (dn->dn_maxblkid != 0)
goto fail;
mutex_enter(&dn->dn_dbufs_mtx);
for (db = avl_first(&dn->dn_dbufs); db != NULL;
db = AVL_NEXT(&dn->dn_dbufs, db)) {
if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID &&
db->db_blkid != DMU_SPILL_BLKID) {
mutex_exit(&dn->dn_dbufs_mtx);
goto fail;
}
}
mutex_exit(&dn->dn_dbufs_mtx);
if (ibs && dn->dn_nlevels != 1)
goto fail;
/* resize the old block */
err = dbuf_hold_impl(dn, 0, 0, TRUE, FALSE, FTAG, &db);
if (err == 0)
dbuf_new_size(db, size, tx);
else if (err != ENOENT)
goto fail;
dnode_setdblksz(dn, size);
dnode_setdirty(dn, tx);
dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = size;
if (ibs) {
dn->dn_indblkshift = ibs;
dn->dn_next_indblkshift[tx->tx_txg&TXG_MASK] = ibs;
}
/* rele after we have fixed the blocksize in the dnode */
if (db)
dbuf_rele(db, FTAG);
rw_exit(&dn->dn_struct_rwlock);
return (0);
fail:
rw_exit(&dn->dn_struct_rwlock);
return (SET_ERROR(ENOTSUP));
}
/* read-holding callers must not rely on the lock being continuously held */
void
dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read)
{
uint64_t txgoff = tx->tx_txg & TXG_MASK;
int epbs, new_nlevels;
uint64_t sz;
ASSERT(blkid != DMU_BONUS_BLKID);
ASSERT(have_read ?
RW_READ_HELD(&dn->dn_struct_rwlock) :
RW_WRITE_HELD(&dn->dn_struct_rwlock));
/*
* if we have a read-lock, check to see if we need to do any work
* before upgrading to a write-lock.
*/
if (have_read) {
if (blkid <= dn->dn_maxblkid)
return;
if (!rw_tryupgrade(&dn->dn_struct_rwlock)) {
rw_exit(&dn->dn_struct_rwlock);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
}
}
if (blkid <= dn->dn_maxblkid)
goto out;
dn->dn_maxblkid = blkid;
/*
* Compute the number of levels necessary to support the new maxblkid.
*/
new_nlevels = 1;
epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
for (sz = dn->dn_nblkptr;
sz <= blkid && sz >= dn->dn_nblkptr; sz <<= epbs)
new_nlevels++;
ASSERT3U(new_nlevels, <=, DN_MAX_LEVELS);
if (new_nlevels > dn->dn_nlevels) {
int old_nlevels = dn->dn_nlevels;
dmu_buf_impl_t *db;
list_t *list;
dbuf_dirty_record_t *new, *dr, *dr_next;
dn->dn_nlevels = new_nlevels;
ASSERT3U(new_nlevels, >, dn->dn_next_nlevels[txgoff]);
dn->dn_next_nlevels[txgoff] = new_nlevels;
/* dirty the left indirects */
db = dbuf_hold_level(dn, old_nlevels, 0, FTAG);
ASSERT(db != NULL);
new = dbuf_dirty(db, tx);
dbuf_rele(db, FTAG);
/* transfer the dirty records to the new indirect */
mutex_enter(&dn->dn_mtx);
mutex_enter(&new->dt.di.dr_mtx);
list = &dn->dn_dirty_records[txgoff];
for (dr = list_head(list); dr; dr = dr_next) {
dr_next = list_next(&dn->dn_dirty_records[txgoff], dr);
if (dr->dr_dbuf->db_level != new_nlevels-1 &&
dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID &&
dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) {
ASSERT(dr->dr_dbuf->db_level == old_nlevels-1);
list_remove(&dn->dn_dirty_records[txgoff], dr);
list_insert_tail(&new->dt.di.dr_children, dr);
dr->dr_parent = new;
}
}
mutex_exit(&new->dt.di.dr_mtx);
mutex_exit(&dn->dn_mtx);
}
out:
if (have_read)
rw_downgrade(&dn->dn_struct_rwlock);
}
static void
dnode_dirty_l1(dnode_t *dn, uint64_t l1blkid, dmu_tx_t *tx)
{
dmu_buf_impl_t *db = dbuf_hold_level(dn, 1, l1blkid, FTAG);
if (db != NULL) {
dmu_buf_will_dirty(&db->db, tx);
dbuf_rele(db, FTAG);
}
}
void
dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx)
{
dmu_buf_impl_t *db;
uint64_t blkoff, blkid, nblks;
int blksz, blkshift, head, tail;
int trunc = FALSE;
int epbs;
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
blksz = dn->dn_datablksz;
blkshift = dn->dn_datablkshift;
epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
if (len == DMU_OBJECT_END) {
len = UINT64_MAX - off;
trunc = TRUE;
}
/*
* First, block align the region to free:
*/
if (ISP2(blksz)) {
head = P2NPHASE(off, blksz);
blkoff = P2PHASE(off, blksz);
if ((off >> blkshift) > dn->dn_maxblkid)
goto out;
} else {
ASSERT(dn->dn_maxblkid == 0);
if (off == 0 && len >= blksz) {
/*
* Freeing the whole block; fast-track this request.
* Note that we won't dirty any indirect blocks,
* which is fine because we will be freeing the entire
* file and thus all indirect blocks will be freed
* by free_children().
*/
blkid = 0;
nblks = 1;
goto done;
} else if (off >= blksz) {
/* Freeing past end-of-data */
goto out;
} else {
/* Freeing part of the block. */
head = blksz - off;
ASSERT3U(head, >, 0);
}
blkoff = off;
}
/* zero out any partial block data at the start of the range */
if (head) {
ASSERT3U(blkoff + head, ==, blksz);
if (len < head)
head = len;
if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off),
TRUE, FALSE, FTAG, &db) == 0) {
caddr_t data;
/* don't dirty if it isn't on disk and isn't dirty */
if (db->db_last_dirty ||
(db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) {
rw_exit(&dn->dn_struct_rwlock);
dmu_buf_will_dirty(&db->db, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
data = db->db.db_data;
bzero(data + blkoff, head);
}
dbuf_rele(db, FTAG);
}
off += head;
len -= head;
}
/* If the range was less than one block, we're done */
if (len == 0)
goto out;
/* If the remaining range is past end of file, we're done */
if ((off >> blkshift) > dn->dn_maxblkid)
goto out;
ASSERT(ISP2(blksz));
if (trunc)
tail = 0;
else
tail = P2PHASE(len, blksz);
ASSERT0(P2PHASE(off, blksz));
/* zero out any partial block data at the end of the range */
if (tail) {
if (len < tail)
tail = len;
if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off+len),
TRUE, FALSE, FTAG, &db) == 0) {
/* don't dirty if not on disk and not dirty */
if (db->db_last_dirty ||
(db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) {
rw_exit(&dn->dn_struct_rwlock);
dmu_buf_will_dirty(&db->db, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
bzero(db->db.db_data, tail);
}
dbuf_rele(db, FTAG);
}
len -= tail;
}
/* If the range did not include a full block, we are done */
if (len == 0)
goto out;
ASSERT(IS_P2ALIGNED(off, blksz));
ASSERT(trunc || IS_P2ALIGNED(len, blksz));
blkid = off >> blkshift;
nblks = len >> blkshift;
if (trunc)
nblks += 1;
/*
* Dirty all the indirect blocks in this range. Note that only
* the first and last indirect blocks can actually be written
* (if they were partially freed) -- they must be dirtied, even if
* they do not exist on disk yet. The interior blocks will
* be freed by free_children(), so they will not actually be written.
* Even though these interior blocks will not be written, we
* dirty them for two reasons:
*
* - It ensures that the indirect blocks remain in memory until
* syncing context. (They have already been prefetched by
* dmu_tx_hold_free(), so we don't have to worry about reading
* them serially here.)
*
* - The dirty space accounting will put pressure on the txg sync
* mechanism to begin syncing, and to delay transactions if there
* is a large amount of freeing. Even though these indirect
* blocks will not be written, we could need to write the same
* amount of space if we copy the freed BPs into deadlists.
*/
if (dn->dn_nlevels > 1) {
uint64_t first, last, i, ibyte;
int shift, err;
first = blkid >> epbs;
dnode_dirty_l1(dn, first, tx);
if (trunc)
last = dn->dn_maxblkid >> epbs;
else
last = (blkid + nblks - 1) >> epbs;
if (last != first)
dnode_dirty_l1(dn, last, tx);
shift = dn->dn_datablkshift + dn->dn_indblkshift -
SPA_BLKPTRSHIFT;
for (i = first + 1; i < last; i++) {
/*
* Set i to the blockid of the next non-hole
* level-1 indirect block at or after i. Note
* that dnode_next_offset() operates in terms of
* level-0-equivalent bytes.
*/
ibyte = i << shift;
err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK,
&ibyte, 2, 1, 0);
i = ibyte >> shift;
if (i >= last)
break;
/*
* Normally we should not see an error, either
* from dnode_next_offset() or dbuf_hold_level()
* (except for ESRCH from dnode_next_offset).
* If there is an i/o error, then when we read
* this block in syncing context, it will use
* ZIO_FLAG_MUSTSUCCEED, and thus hang/panic according
* to the "failmode" property. dnode_next_offset()
* doesn't have a flag to indicate MUSTSUCCEED.
*/
if (err != 0)
break;
dnode_dirty_l1(dn, i, tx);
}
}
done:
/*
* Add this range to the dnode range list.
* We will finish up this free operation in the syncing phase.
*/
mutex_enter(&dn->dn_mtx);
{
int txgoff = tx->tx_txg & TXG_MASK;
if (dn->dn_free_ranges[txgoff] == NULL) {
dn->dn_free_ranges[txgoff] =
range_tree_create(NULL, NULL, &dn->dn_mtx);
}
range_tree_clear(dn->dn_free_ranges[txgoff], blkid, nblks);
range_tree_add(dn->dn_free_ranges[txgoff], blkid, nblks);
}
dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n",
blkid, nblks, tx->tx_txg);
mutex_exit(&dn->dn_mtx);
dbuf_free_range(dn, blkid, blkid + nblks - 1, tx);
dnode_setdirty(dn, tx);
out:
rw_exit(&dn->dn_struct_rwlock);
}
static boolean_t
dnode_spill_freed(dnode_t *dn)
{
int i;
mutex_enter(&dn->dn_mtx);
for (i = 0; i < TXG_SIZE; i++) {
if (dn->dn_rm_spillblk[i] == DN_KILL_SPILLBLK)
break;
}
mutex_exit(&dn->dn_mtx);
return (i < TXG_SIZE);
}
/* return TRUE if this blkid was freed in a recent txg, or FALSE if it wasn't */
uint64_t
dnode_block_freed(dnode_t *dn, uint64_t blkid)
{
void *dp = spa_get_dsl(dn->dn_objset->os_spa);
int i;
if (blkid == DMU_BONUS_BLKID)
return (FALSE);
/*
* If we're in the process of opening the pool, dp will not be
* set yet, but there shouldn't be anything dirty.
*/
if (dp == NULL)
return (FALSE);
if (dn->dn_free_txg)
return (TRUE);
if (blkid == DMU_SPILL_BLKID)
return (dnode_spill_freed(dn));
mutex_enter(&dn->dn_mtx);
for (i = 0; i < TXG_SIZE; i++) {
if (dn->dn_free_ranges[i] != NULL &&
range_tree_contains(dn->dn_free_ranges[i], blkid, 1))
break;
}
mutex_exit(&dn->dn_mtx);
return (i < TXG_SIZE);
}
/* call from syncing context when we actually write/free space for this dnode */
void
dnode_diduse_space(dnode_t *dn, int64_t delta)
{
uint64_t space;
dprintf_dnode(dn, "dn=%p dnp=%p used=%llu delta=%lld\n",
dn, dn->dn_phys,
(u_longlong_t)dn->dn_phys->dn_used,
(longlong_t)delta);
mutex_enter(&dn->dn_mtx);
space = DN_USED_BYTES(dn->dn_phys);
if (delta > 0) {
ASSERT3U(space + delta, >=, space); /* no overflow */
} else {
ASSERT3U(space, >=, -delta); /* no underflow */
}
space += delta;
if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) {
ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0);
ASSERT0(P2PHASE(space, 1<<DEV_BSHIFT));
dn->dn_phys->dn_used = space >> DEV_BSHIFT;
} else {
dn->dn_phys->dn_used = space;
dn->dn_phys->dn_flags |= DNODE_FLAG_USED_BYTES;
}
mutex_exit(&dn->dn_mtx);
}
/*
* Scans a block at the indicated "level" looking for a hole or data,
* depending on 'flags'.
*
* If level > 0, then we are scanning an indirect block looking at its
* pointers. If level == 0, then we are looking at a block of dnodes.
*
* If we don't find what we are looking for in the block, we return ESRCH.
* Otherwise, return with *offset pointing to the beginning (if searching
* forwards) or end (if searching backwards) of the range covered by the
* block pointer we matched on (or dnode).
*
* The basic search algorithm used below by dnode_next_offset() is to
* use this function to search up the block tree (widen the search) until
* we find something (i.e., we don't return ESRCH) and then search back
* down the tree (narrow the search) until we reach our original search
* level.
*/
static int
dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset,
int lvl, uint64_t blkfill, uint64_t txg)
{
dmu_buf_impl_t *db = NULL;
void *data = NULL;
uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
uint64_t epb = 1ULL << epbs;
uint64_t minfill, maxfill;
boolean_t hole;
int i, inc, error, span;
hole = ((flags & DNODE_FIND_HOLE) != 0);
inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1;
ASSERT(txg == 0 || !hole);
if (lvl == dn->dn_phys->dn_nlevels) {
error = 0;
epb = dn->dn_phys->dn_nblkptr;
data = dn->dn_phys->dn_blkptr;
} else {
uint64_t blkid = dbuf_whichblock(dn, lvl, *offset);
error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FALSE, FTAG, &db);
if (error) {
if (error != ENOENT)
return (error);
if (hole)
return (0);
/*
* This can only happen when we are searching up
* the block tree for data. We don't really need to
* adjust the offset, as we will just end up looking
* at the pointer to this block in its parent, and its
* going to be unallocated, so we will skip over it.
*/
return (SET_ERROR(ESRCH));
}
error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT);
if (error) {
dbuf_rele(db, FTAG);
return (error);
}
data = db->db.db_data;
}
if (db != NULL && txg != 0 && (db->db_blkptr == NULL ||
db->db_blkptr->blk_birth <= txg ||
BP_IS_HOLE(db->db_blkptr))) {
/*
* This can only happen when we are searching up the tree
* and these conditions mean that we need to keep climbing.
*/
error = SET_ERROR(ESRCH);
} else if (lvl == 0) {
dnode_phys_t *dnp = data;
ASSERT(dn->dn_type == DMU_OT_DNODE);
ASSERT(!(flags & DNODE_FIND_BACKWARDS));
for (i = (*offset >> DNODE_SHIFT) & (blkfill - 1);
i < blkfill; i += dnp[i].dn_extra_slots + 1) {
if ((dnp[i].dn_type == DMU_OT_NONE) == hole)
break;
}
if (i == blkfill)
error = SET_ERROR(ESRCH);
*offset = (*offset & ~(DNODE_BLOCK_SIZE - 1)) +
(i << DNODE_SHIFT);
} else {
blkptr_t *bp = data;
uint64_t start = *offset;
span = (lvl - 1) * epbs + dn->dn_datablkshift;
minfill = 0;
maxfill = blkfill << ((lvl - 1) * epbs);
if (hole)
maxfill--;
else
minfill++;
if (span >= 8 * sizeof (*offset)) {
/* This only happens on the highest indirection level */
ASSERT3U((lvl - 1), ==, dn->dn_phys->dn_nlevels - 1);
*offset = 0;
} else {
*offset = *offset >> span;
}
for (i = BF64_GET(*offset, 0, epbs);
i >= 0 && i < epb; i += inc) {
if (BP_GET_FILL(&bp[i]) >= minfill &&
BP_GET_FILL(&bp[i]) <= maxfill &&
(hole || bp[i].blk_birth > txg))
break;
if (inc > 0 || *offset > 0)
*offset += inc;
}
if (span >= 8 * sizeof (*offset)) {
*offset = start;
} else {
*offset = *offset << span;
}
if (inc < 0) {
/* traversing backwards; position offset at the end */
ASSERT3U(*offset, <=, start);
*offset = MIN(*offset + (1ULL << span) - 1, start);
} else if (*offset < start) {
*offset = start;
}
if (i < 0 || i >= epb)
error = SET_ERROR(ESRCH);
}
if (db)
dbuf_rele(db, FTAG);
return (error);
}
/*
* Find the next hole, data, or sparse region at or after *offset.
* The value 'blkfill' tells us how many items we expect to find
* in an L0 data block; this value is 1 for normal objects,
* DNODES_PER_BLOCK for the meta dnode, and some fraction of
* DNODES_PER_BLOCK when searching for sparse regions thereof.
*
* Examples:
*
* dnode_next_offset(dn, flags, offset, 1, 1, 0);
* Finds the next/previous hole/data in a file.
* Used in dmu_offset_next().
*
* dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg);
* Finds the next free/allocated dnode an objset's meta-dnode.
* Only finds objects that have new contents since txg (ie.
* bonus buffer changes and content removal are ignored).
* Used in dmu_object_next().
*
* dnode_next_offset(mdn, DNODE_FIND_HOLE, offset, 2, DNODES_PER_BLOCK >> 2, 0);
* Finds the next L2 meta-dnode bp that's at most 1/4 full.
* Used in dmu_object_alloc().
*/
int
dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset,
int minlvl, uint64_t blkfill, uint64_t txg)
{
uint64_t initial_offset = *offset;
int lvl, maxlvl;
int error = 0;
if (!(flags & DNODE_FIND_HAVELOCK))
rw_enter(&dn->dn_struct_rwlock, RW_READER);
if (dn->dn_phys->dn_nlevels == 0) {
error = SET_ERROR(ESRCH);
goto out;
}
if (dn->dn_datablkshift == 0) {
if (*offset < dn->dn_datablksz) {
if (flags & DNODE_FIND_HOLE)
*offset = dn->dn_datablksz;
} else {
error = SET_ERROR(ESRCH);
}
goto out;
}
maxlvl = dn->dn_phys->dn_nlevels;
for (lvl = minlvl; lvl <= maxlvl; lvl++) {
error = dnode_next_offset_level(dn,
flags, offset, lvl, blkfill, txg);
if (error != ESRCH)
break;
}
while (error == 0 && --lvl >= minlvl) {
error = dnode_next_offset_level(dn,
flags, offset, lvl, blkfill, txg);
}
/*
* There's always a "virtual hole" at the end of the object, even
* if all BP's which physically exist are non-holes.
*/
if ((flags & DNODE_FIND_HOLE) && error == ESRCH && txg == 0 &&
minlvl == 1 && blkfill == 1 && !(flags & DNODE_FIND_BACKWARDS)) {
error = 0;
}
if (error == 0 && (flags & DNODE_FIND_BACKWARDS ?
initial_offset < *offset : initial_offset > *offset))
error = SET_ERROR(ESRCH);
out:
if (!(flags & DNODE_FIND_HAVELOCK))
rw_exit(&dn->dn_struct_rwlock);
return (error);
}
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