static void
dmu_objset_sync_dnodes(list_t *list, list_t *newlist, dmu_tx_t *tx)
{
dnode_t *dn;
while (dn = list_head(list)) {
ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
ASSERT(dn->dn_dbuf->db_data_pending);
/*
* Initialize dn_zio outside dnode_sync() because the
* meta-dnode needs to set it ouside dnode_sync().
*/
dn->dn_zio = dn->dn_dbuf->db_data_pending->dr_zio;
ASSERT(dn->dn_zio);
ASSERT3U(dn->dn_nlevels, <=, DN_MAX_LEVELS);
list_remove(list, dn);
if (newlist) {
(void) dnode_add_ref(dn, newlist);
list_insert_tail(newlist, dn);
}
dnode_sync(dn, tx);
}
}
/*
* returns ENOENT, EIO, or 0.
*/
int
dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **dbp)
{
dnode_t *dn;
dmu_buf_impl_t *db;
int error;
error = dnode_hold(os->os, object, FTAG, &dn);
if (error)
return (error);
rw_enter(&dn->dn_struct_rwlock, RW_READER);
if (dn->dn_bonus == NULL) {
rw_exit(&dn->dn_struct_rwlock);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
if (dn->dn_bonus == NULL)
dbuf_create_bonus(dn);
}
db = dn->dn_bonus;
rw_exit(&dn->dn_struct_rwlock);
/* as long as the bonus buf is held, the dnode will be held */
if (refcount_add(&db->db_holds, tag) == 1)
VERIFY(dnode_add_ref(dn, db));
dnode_rele(dn, FTAG);
VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED));
*dbp = &db->db;
return (0);
}
int
dmu_objset_evict_dbufs(objset_t *os)
{
dnode_t *dn;
mutex_enter(&os->os_lock);
/* process the mdn last, since the other dnodes have holds on it */
list_remove(&os->os_dnodes, DMU_META_DNODE(os));
list_insert_tail(&os->os_dnodes, DMU_META_DNODE(os));
/*
* Find the first dnode with holds. We have to do this dance
* because dnode_add_ref() only works if you already have a
* hold. If there are no holds then it has no dbufs so OK to
* skip.
*/
for (dn = list_head(&os->os_dnodes);
dn && !dnode_add_ref(dn, FTAG);
dn = list_next(&os->os_dnodes, dn))
continue;
while (dn) {
dnode_t *next_dn = dn;
do {
next_dn = list_next(&os->os_dnodes, next_dn);
} while (next_dn && !dnode_add_ref(next_dn, FTAG));
mutex_exit(&os->os_lock);
dnode_evict_dbufs(dn);
dnode_rele(dn, FTAG);
mutex_enter(&os->os_lock);
dn = next_dn;
}
dn = list_head(&os->os_dnodes);
mutex_exit(&os->os_lock);
return (dn != DMU_META_DNODE(os));
}
/*
* returns ENOENT, EIO, or 0.
*/
int
dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **dbp)
{
dnode_t *dn;
dmu_buf_impl_t *db;
int error;
error = dnode_hold(os, object, FTAG, &dn);
if (error)
return (error);
rw_enter(&dn->dn_struct_rwlock, RW_READER);
if (dn->dn_bonus == NULL) {
rw_exit(&dn->dn_struct_rwlock);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
if (dn->dn_bonus == NULL)
dbuf_create_bonus(dn);
}
db = dn->dn_bonus;
/* as long as the bonus buf is held, the dnode will be held */
if (refcount_add(&db->db_holds, tag) == 1) {
VERIFY(dnode_add_ref(dn, db));
atomic_inc_32(&dn->dn_dbufs_count);
}
/*
* Wait to drop dn_struct_rwlock until after adding the bonus dbuf's
* hold and incrementing the dbuf count to ensure that dnode_move() sees
* a dnode hold for every dbuf.
*/
rw_exit(&dn->dn_struct_rwlock);
dnode_rele(dn, FTAG);
VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH));
*dbp = &db->db;
return (0);
}
void
dmu_objset_evict_dbufs(objset_t *os)
{
dnode_t dn_marker;
dnode_t *dn;
mutex_enter(&os->os_lock);
dn = list_head(&os->os_dnodes);
while (dn != NULL) {
/*
* Skip dnodes without holds. We have to do this dance
* because dnode_add_ref() only works if there is already a
* hold. If the dnode has no holds, then it has no dbufs.
*/
if (dnode_add_ref(dn, FTAG)) {
list_insert_after(&os->os_dnodes, dn, &dn_marker);
mutex_exit(&os->os_lock);
dnode_evict_dbufs(dn);
dnode_rele(dn, FTAG);
mutex_enter(&os->os_lock);
dn = list_next(&os->os_dnodes, &dn_marker);
list_remove(&os->os_dnodes, &dn_marker);
} else {
dn = list_next(&os->os_dnodes, dn);
}
}
mutex_exit(&os->os_lock);
if (DMU_USERUSED_DNODE(os) != NULL) {
dnode_evict_dbufs(DMU_GROUPUSED_DNODE(os));
dnode_evict_dbufs(DMU_USERUSED_DNODE(os));
}
dnode_evict_dbufs(DMU_META_DNODE(os));
}