/*
* 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, 2015 by Delphix. All rights reserved.
* Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
* Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
*/
#ifndef _SYS_DBUF_H
#define _SYS_DBUF_H
#include <sys/dmu.h>
#include <sys/spa.h>
#include <sys/txg.h>
#include <sys/zio.h>
#include <sys/arc.h>
#include <sys/zfs_context.h>
#include <sys/refcount.h>
#include <sys/zrlock.h>
#include <sys/multilist.h>
#ifdef __cplusplus
extern "C" {
#endif
#define IN_DMU_SYNC 2
/*
* define flags for dbuf_read
*/
#define DB_RF_MUST_SUCCEED (1 << 0)
#define DB_RF_CANFAIL (1 << 1)
#define DB_RF_HAVESTRUCT (1 << 2)
#define DB_RF_NOPREFETCH (1 << 3)
#define DB_RF_NEVERWAIT (1 << 4)
#define DB_RF_CACHED (1 << 5)
/*
* The simplified state transition diagram for dbufs looks like:
*
* +----> READ ----+
* | |
* | V
* (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
* | ^ ^
* | | |
* +----> FILL ----+ |
* | |
* | |
* +--------> NOFILL -------+
*
* DB_SEARCH is an invalid state for a dbuf. It is used by dbuf_free_range
* to find all dbufs in a range of a dnode and must be less than any other
* dbuf_states_t (see comment on dn_dbufs in dnode.h).
*/
typedef enum dbuf_states {
DB_SEARCH = -1,
DB_UNCACHED,
DB_FILL,
DB_NOFILL,
DB_READ,
DB_CACHED,
DB_EVICTING
} dbuf_states_t;
struct dnode;
struct dmu_tx;
/*
* level = 0 means the user data
* level = 1 means the single indirect block
* etc.
*/
struct dmu_buf_impl;
typedef enum override_states {
DR_NOT_OVERRIDDEN,
DR_IN_DMU_SYNC,
DR_OVERRIDDEN
} override_states_t;
typedef struct dbuf_dirty_record {
/* link on our parents dirty list */
list_node_t dr_dirty_node;
/* transaction group this data will sync in */
uint64_t dr_txg;
/* zio of outstanding write IO */
zio_t *dr_zio;
/* pointer back to our dbuf */
struct dmu_buf_impl *dr_dbuf;
/* pointer to next dirty record */
struct dbuf_dirty_record *dr_next;
/* pointer to parent dirty record */
struct dbuf_dirty_record *dr_parent;
/* How much space was changed to dsl_pool_dirty_space() for this? */
unsigned int dr_accounted;
/* A copy of the bp that points to us */
blkptr_t dr_bp_copy;
union dirty_types {
struct dirty_indirect {
/* protect access to list */
kmutex_t dr_mtx;
/* Our list of dirty children */
list_t dr_children;
} di;
struct dirty_leaf {
/*
* dr_data is set when we dirty the buffer
* so that we can retain the pointer even if it
* gets COW'd in a subsequent transaction group.
*/
arc_buf_t *dr_data;
blkptr_t dr_overridden_by;
override_states_t dr_override_state;
uint8_t dr_copies;
boolean_t dr_nopwrite;
} dl;
} dt;
} dbuf_dirty_record_t;
typedef struct dmu_buf_impl {
/*
* The following members are immutable, with the exception of
* db.db_data, which is protected by db_mtx.
*/
/* the publicly visible structure */
dmu_buf_t db;
/* the objset we belong to */
struct objset *db_objset;
/*
* handle to safely access the dnode we belong to (NULL when evicted)
*/
struct dnode_handle *db_dnode_handle;
/*
* our parent buffer; if the dnode points to us directly,
* db_parent == db_dnode_handle->dnh_dnode->dn_dbuf
* only accessed by sync thread ???
* (NULL when evicted)
* May change from NULL to non-NULL under the protection of db_mtx
* (see dbuf_check_blkptr())
*/
struct dmu_buf_impl *db_parent;
/*
* link for hash table of all dmu_buf_impl_t's
*/
struct dmu_buf_impl *db_hash_next;
/* our block number */
uint64_t db_blkid;
/*
* Pointer to the blkptr_t which points to us. May be NULL if we
* don't have one yet. (NULL when evicted)
*/
blkptr_t *db_blkptr;
/*
* Our indirection level. Data buffers have db_level==0.
* Indirect buffers which point to data buffers have
* db_level==1. etc. Buffers which contain dnodes have
* db_level==0, since the dnodes are stored in a file.
*/
uint8_t db_level;
/* db_mtx protects the members below */
kmutex_t db_mtx;
/*
* Current state of the buffer
*/
dbuf_states_t db_state;
/*
* Refcount accessed by dmu_buf_{hold,rele}.
* If nonzero, the buffer can't be destroyed.
* Protected by db_mtx.
*/
refcount_t db_holds;
/* buffer holding our data */
arc_buf_t *db_buf;
kcondvar_t db_changed;
dbuf_dirty_record_t *db_data_pending;
/* pointer to most recent dirty record for this buffer */
dbuf_dirty_record_t *db_last_dirty;
/*
* Our link on the owner dnodes's dn_dbufs list.
* Protected by its dn_dbufs_mtx.
*/
avl_node_t db_link;
/*
* Link in dbuf_cache.
*/
multilist_node_t db_cache_link;
/* Data which is unique to data (leaf) blocks: */
/* User callback information. */
dmu_buf_user_t *db_user;
/*
* Evict user data as soon as the dirty and reference
* counts are equal.
*/
uint8_t db_user_immediate_evict;
/*
* This block was freed while a read or write was
* active.
*/
uint8_t db_freed_in_flight;
/*
* dnode_evict_dbufs() or dnode_evict_bonus() tried to
* evict this dbuf, but couldn't due to outstanding
* references. Evict once the refcount drops to 0.
*/
uint8_t db_pending_evict;
uint8_t db_dirtycnt;
} dmu_buf_impl_t;
/* Note: the dbuf hash table is exposed only for the mdb module */
#define DBUF_MUTEXES 256
#define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)])
typedef struct dbuf_hash_table {
uint64_t hash_table_mask;
dmu_buf_impl_t **hash_table;
kmutex_t hash_mutexes[DBUF_MUTEXES];
} dbuf_hash_table_t;
uint64_t dbuf_whichblock(struct dnode *di, int64_t level, uint64_t offset);
dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data);
void dbuf_create_bonus(struct dnode *dn);
int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx);
void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag);
void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag);
dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
void *tag);
int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid,
boolean_t fail_sparse, boolean_t fail_uncached,
void *tag, dmu_buf_impl_t **dbp);
void dbuf_prefetch(struct dnode *dn, int64_t level, uint64_t blkid,
zio_priority_t prio, arc_flags_t aflags);
void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
boolean_t dbuf_try_add_ref(dmu_buf_t *db, objset_t *os, uint64_t obj,
uint64_t blkid, void *tag);
uint64_t dbuf_refcount(dmu_buf_impl_t *db);
void dbuf_rele(dmu_buf_impl_t *db, void *tag);
void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag);
dmu_buf_impl_t *dbuf_find(struct objset *os, uint64_t object, uint8_t level,
uint64_t blkid);
int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db);
void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
bp_embedded_type_t etype, enum zio_compress comp,
int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx);
void dbuf_destroy(dmu_buf_impl_t *db);
void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
void dbuf_unoverride(dbuf_dirty_record_t *dr);
void dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx);
void dbuf_release_bp(dmu_buf_impl_t *db);
boolean_t dbuf_can_remap(const dmu_buf_impl_t *buf);
void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
struct dmu_tx *);
void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
#define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
#define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
#define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
#define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
#define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
void dbuf_init(void);
void dbuf_fini(void);
boolean_t dbuf_is_metadata(dmu_buf_impl_t *db);
#define DBUF_GET_BUFC_TYPE(_db) \
(dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
#define DBUF_IS_CACHEABLE(_db) \
((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
(dbuf_is_metadata(_db) && \
((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
#define DBUF_IS_L2CACHEABLE(_db) \
((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
(dbuf_is_metadata(_db) && \
((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
#define DNODE_LEVEL_IS_L2CACHEABLE(_dn, _level) \
((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_ALL || \
(((_level) > 0 || \
DMU_OT_IS_METADATA((_dn)->dn_handle->dnh_dnode->dn_type)) && \
((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
#ifdef ZFS_DEBUG
/*
* There should be a ## between the string literal and fmt, to make it
* clear that we're joining two strings together, but gcc does not
* support that preprocessor token.
*/
#define dprintf_dbuf(dbuf, fmt, ...) do { \
if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
char __db_buf[32]; \
uint64_t __db_obj = (dbuf)->db.db_object; \
if (__db_obj == DMU_META_DNODE_OBJECT) \
(void) strcpy(__db_buf, "mdn"); \
else \
(void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
(u_longlong_t)__db_obj); \
dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
"obj=%s lvl=%u blkid=%lld " fmt, \
__db_buf, (dbuf)->db_level, \
(u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
} \
_NOTE(CONSTCOND) } while (0)
#define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \
dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
kmem_free(__blkbuf, BP_SPRINTF_LEN); \
} \
_NOTE(CONSTCOND) } while (0)
#define DBUF_VERIFY(db) dbuf_verify(db)
#else
#define dprintf_dbuf(db, fmt, ...)
#define dprintf_dbuf_bp(db, bp, fmt, ...)
#define DBUF_VERIFY(db)
#endif
#ifdef __cplusplus
}
#endif
#endif /* _SYS_DBUF_H */
