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mirror_zfs/module/zfs/dmu.c
Prakash Surya 1ce23dcaff OpenZFS 8585 - improve batching done in zil_commit() 
Authored by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Brad Lewis <brad.lewis@delphix.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Dan McDonald <danmcd@joyent.com>
Ported-by: Prakash Surya <prakash.surya@delphix.com>

Problem
=======

The current implementation of zil_commit() can introduce significant
latency, beyond what is inherent due to the latency of the underlying
storage. The additional latency comes from two main problems:

 1. When there's outstanding ZIL blocks being written (i.e. there's
    already a "writer thread" in progress), then any new calls to
    zil_commit() will block waiting for the currently oustanding ZIL
    blocks to complete. The blocks written for each "writer thread" is
    coined a "batch", and there can only ever be a single "batch" being
    written at a time. When a batch is being written, any new ZIL
    transactions will have to wait for the next batch to be written,
    which won't occur until the current batch finishes.

    As a result, the underlying storage may not be used as efficiently
    as possible. While "new" threads enter zil_commit() and are blocked
    waiting for the next batch, it's possible that the underlying
    storage isn't fully utilized by the current batch of ZIL blocks. In
    that case, it'd be better to allow these new threads to generate
    (and issue) a new ZIL block, such that it could be serviced by the
    underlying storage concurrently with the other ZIL blocks that are
    being serviced.

 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch"
    to complete, prior to zil_commit() returning. The size of any given
    batch is proportional to the number of ZIL transaction in the queue
    at the time that the batch starts processing the queue; which
    doesn't occur until the previous batch completes. Thus, if there's a
    lot of transactions in the queue, the batch could be composed of
    many ZIL blocks, and each call to zil_commit() will have to wait for
    all of these writes to complete (even if the thread calling
    zil_commit() only cared about one of the transactions in the batch).

To further complicate the situation, these two issues result in the
following side effect:

 3. If a given batch takes longer to complete than normal, this results
    in larger batch sizes, which then take longer to complete and
    further drive up the latency of zil_commit(). This can occur for a
    number of reasons, including (but not limited to): transient changes
    in the workload, and storage latency irregularites.

Solution
========

The solution attempted by this change has the following goals:

 1. no on-disk changes; maintain current on-disk format.
 2. modify the "batch size" to be equal to the "ZIL block size".
 3. allow new batches to be generated and issued to disk, while there's
    already batches being serviced by the disk.
 4. allow zil_commit() to wait for as few ZIL blocks as possible.
 5. use as few ZIL blocks as possible, for the same amount of ZIL
    transactions, without introducing significant latency to any
    individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks.

In theory, with these goals met, the new allgorithm will allow the
following improvements:

 1. new ZIL blocks can be generated and issued, while there's already
    oustanding ZIL blocks being serviced by the storage.
 2. the latency of zil_commit() should be proportional to the underlying
    storage latency, rather than the incoming synchronous workload.

Porting Notes
=============

Due to the changes made in commit 119a394ab0, the lifetime of an itx
structure differs than in OpenZFS. Specifically, the itx structure is
kept around until the data associated with the itx is considered to be
safe on disk; this is so that the itx's callback can be called after the
data is committed to stable storage. Since OpenZFS doesn't have this itx
callback mechanism, it's able to destroy the itx structure immediately
after the itx is committed to an lwb (before the lwb is written to
disk).

To support this difference, and to ensure the itx's callbacks can still
be called after the itx's data is on disk, a few changes had to be made:

  * A list of itxs was added to the lwb structure. This list contains
    all of the itxs that have been committed to the lwb, such that the
    callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(),
    after the data for the itxs is committed to disk.

  * A list of itxs was added on the stack of the zil_process_commit_list()
    function; the "nolwb_itxs" list. In some circumstances, an itx may
    not be committed to an lwb (e.g. if allocating the "next" ZIL block
    on disk fails), so this list is used to keep track of which itxs
    fall into this state, such that their callbacks can be called after
    the ZIL's writer pipeline is "stalled".

  * The logic to actually call the itx's callback was moved into the
    zil_itx_destroy() function. Since all consumers of zil_itx_destroy()
    were effectively performing the same logic (i.e. if callback is
    non-null, call the callback), it seemed like useful code cleanup to
    consolidate this logic into a single function.

Additionally, the existing Linux tracepoint infrastructure dealing with
the ZIL's probes and structures had to be updated to reflect these code
changes. Specifically:

  * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be
    removed from "trace_zil.h" as well.

  * Some of the zilog structure's fields were removed, which affected
    the tracepoint definitions of the structure.

  * New tracepoints had to be added for the following 3 new probes:
      * zil__process__commit__itx
      * zil__process__normal__itx
      * zil__commit__io__error

OpenZFS-issue: https://www.illumos.org/issues/8585
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a
Closes #6566
2017-12-05 09:39:16 -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) 2011, 2017 by Delphix. All rights reserved.
* Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
* Copyright (c) 2013, Joyent, Inc. All rights reserved.
* Copyright (c) 2016, Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2015 by Chunwei Chen. All rights reserved.
*/
#include <sys/dmu.h>
#include <sys/dmu_impl.h>
#include <sys/dmu_tx.h>
#include <sys/dbuf.h>
#include <sys/dnode.h>
#include <sys/zfs_context.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_traverse.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_synctask.h>
#include <sys/dsl_prop.h>
#include <sys/dmu_zfetch.h>
#include <sys/zfs_ioctl.h>
#include <sys/zap.h>
#include <sys/zio_checksum.h>
#include <sys/zio_compress.h>
#include <sys/sa.h>
#include <sys/zfeature.h>
#include <sys/abd.h>
#include <sys/trace_dmu.h>
#include <sys/zfs_rlock.h>
#ifdef _KERNEL
#include <sys/vmsystm.h>
#include <sys/zfs_znode.h>
#endif
/*
* Enable/disable nopwrite feature.
*/
int zfs_nopwrite_enabled = 1;
/*
* Tunable to control percentage of dirtied blocks from frees in one TXG.
* After this threshold is crossed, additional dirty blocks from frees
* wait until the next TXG.
* A value of zero will disable this throttle.
*/
unsigned long zfs_per_txg_dirty_frees_percent = 30;
/*
* Enable/disable forcing txg sync when dirty in dmu_offset_next.
*/
int zfs_dmu_offset_next_sync = 0;
const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = {
{ DMU_BSWAP_UINT8, TRUE, FALSE, "unallocated" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "object directory" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "object array" },
{ DMU_BSWAP_UINT8, TRUE, FALSE, "packed nvlist" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "packed nvlist size" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "bpobj" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "bpobj header" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "SPA space map header" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "SPA space map" },
{ DMU_BSWAP_UINT64, TRUE, TRUE, "ZIL intent log" },
{ DMU_BSWAP_DNODE, TRUE, TRUE, "DMU dnode" },
{ DMU_BSWAP_OBJSET, TRUE, FALSE, "DMU objset" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "DSL directory" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DSL directory child map"},
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DSL dataset snap map" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DSL props" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "DSL dataset" },
{ DMU_BSWAP_ZNODE, TRUE, FALSE, "ZFS znode" },
{ DMU_BSWAP_OLDACL, TRUE, TRUE, "ZFS V0 ACL" },
{ DMU_BSWAP_UINT8, FALSE, TRUE, "ZFS plain file" },
{ DMU_BSWAP_ZAP, TRUE, TRUE, "ZFS directory" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "ZFS master node" },
{ DMU_BSWAP_ZAP, TRUE, TRUE, "ZFS delete queue" },
{ DMU_BSWAP_UINT8, FALSE, TRUE, "zvol object" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "zvol prop" },
{ DMU_BSWAP_UINT8, FALSE, TRUE, "other uint8[]" },
{ DMU_BSWAP_UINT64, FALSE, TRUE, "other uint64[]" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "other ZAP" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "persistent error log" },
{ DMU_BSWAP_UINT8, TRUE, FALSE, "SPA history" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "SPA history offsets" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "Pool properties" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DSL permissions" },
{ DMU_BSWAP_ACL, TRUE, TRUE, "ZFS ACL" },
{ DMU_BSWAP_UINT8, TRUE, TRUE, "ZFS SYSACL" },
{ DMU_BSWAP_UINT8, TRUE, TRUE, "FUID table" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "FUID table size" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DSL dataset next clones"},
{ DMU_BSWAP_ZAP, TRUE, FALSE, "scan work queue" },
{ DMU_BSWAP_ZAP, TRUE, TRUE, "ZFS user/group used" },
{ DMU_BSWAP_ZAP, TRUE, TRUE, "ZFS user/group quota" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "snapshot refcount tags"},
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DDT ZAP algorithm" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DDT statistics" },
{ DMU_BSWAP_UINT8, TRUE, TRUE, "System attributes" },
{ DMU_BSWAP_ZAP, TRUE, TRUE, "SA master node" },
{ DMU_BSWAP_ZAP, TRUE, TRUE, "SA attr registration" },
{ DMU_BSWAP_ZAP, TRUE, TRUE, "SA attr layouts" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "scan translations" },
{ DMU_BSWAP_UINT8, FALSE, TRUE, "deduplicated block" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DSL deadlist map" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "DSL deadlist map hdr" },
{ DMU_BSWAP_ZAP, TRUE, FALSE, "DSL dir clones" },
{ DMU_BSWAP_UINT64, TRUE, FALSE, "bpobj subobj" }
};
const dmu_object_byteswap_info_t dmu_ot_byteswap[DMU_BSWAP_NUMFUNCS] = {
{ byteswap_uint8_array, "uint8" },
{ byteswap_uint16_array, "uint16" },
{ byteswap_uint32_array, "uint32" },
{ byteswap_uint64_array, "uint64" },
{ zap_byteswap, "zap" },
{ dnode_buf_byteswap, "dnode" },
{ dmu_objset_byteswap, "objset" },
{ zfs_znode_byteswap, "znode" },
{ zfs_oldacl_byteswap, "oldacl" },
{ zfs_acl_byteswap, "acl" }
};
int
dmu_buf_hold_noread_by_dnode(dnode_t *dn, uint64_t offset,
void *tag, dmu_buf_t **dbp)
{
uint64_t blkid;
dmu_buf_impl_t *db;
blkid = dbuf_whichblock(dn, 0, offset);
rw_enter(&dn->dn_struct_rwlock, RW_READER);
db = dbuf_hold(dn, blkid, tag);
rw_exit(&dn->dn_struct_rwlock);
if (db == NULL) {
*dbp = NULL;
return (SET_ERROR(EIO));
}
*dbp = &db->db;
return (0);
}
int
dmu_buf_hold_noread(objset_t *os, uint64_t object, uint64_t offset,
void *tag, dmu_buf_t **dbp)
{
dnode_t *dn;
uint64_t blkid;
dmu_buf_impl_t *db;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
blkid = dbuf_whichblock(dn, 0, offset);
rw_enter(&dn->dn_struct_rwlock, RW_READER);
db = dbuf_hold(dn, blkid, tag);
rw_exit(&dn->dn_struct_rwlock);
dnode_rele(dn, FTAG);
if (db == NULL) {
*dbp = NULL;
return (SET_ERROR(EIO));
}
*dbp = &db->db;
return (err);
}
int
dmu_buf_hold_by_dnode(dnode_t *dn, uint64_t offset,
void *tag, dmu_buf_t **dbp, int flags)
{
int err;
int db_flags = DB_RF_CANFAIL;
if (flags & DMU_READ_NO_PREFETCH)
db_flags |= DB_RF_NOPREFETCH;
if (flags & DMU_READ_NO_DECRYPT)
db_flags |= DB_RF_NO_DECRYPT;
err = dmu_buf_hold_noread_by_dnode(dn, offset, tag, dbp);
if (err == 0) {
dmu_buf_impl_t *db = (dmu_buf_impl_t *)(*dbp);
err = dbuf_read(db, NULL, db_flags);
if (err != 0) {
dbuf_rele(db, tag);
*dbp = NULL;
}
}
return (err);
}
int
dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
void *tag, dmu_buf_t **dbp, int flags)
{
int err;
int db_flags = DB_RF_CANFAIL;
if (flags & DMU_READ_NO_PREFETCH)
db_flags |= DB_RF_NOPREFETCH;
if (flags & DMU_READ_NO_DECRYPT)
db_flags |= DB_RF_NO_DECRYPT;
err = dmu_buf_hold_noread(os, object, offset, tag, dbp);
if (err == 0) {
dmu_buf_impl_t *db = (dmu_buf_impl_t *)(*dbp);
err = dbuf_read(db, NULL, db_flags);
if (err != 0) {
dbuf_rele(db, tag);
*dbp = NULL;
}
}
return (err);
}
int
dmu_bonus_max(void)
{
return (DN_OLD_MAX_BONUSLEN);
}
int
dmu_set_bonus(dmu_buf_t *db_fake, int newsize, dmu_tx_t *tx)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
dnode_t *dn;
int error;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
if (dn->dn_bonus != db) {
error = SET_ERROR(EINVAL);
} else if (newsize < 0 || newsize > db_fake->db_size) {
error = SET_ERROR(EINVAL);
} else {
dnode_setbonuslen(dn, newsize, tx);
error = 0;
}
DB_DNODE_EXIT(db);
return (error);
}
int
dmu_set_bonustype(dmu_buf_t *db_fake, dmu_object_type_t type, dmu_tx_t *tx)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
dnode_t *dn;
int error;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
if (!DMU_OT_IS_VALID(type)) {
error = SET_ERROR(EINVAL);
} else if (dn->dn_bonus != db) {
error = SET_ERROR(EINVAL);
} else {
dnode_setbonus_type(dn, type, tx);
error = 0;
}
DB_DNODE_EXIT(db);
return (error);
}
dmu_object_type_t
dmu_get_bonustype(dmu_buf_t *db_fake)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
dnode_t *dn;
dmu_object_type_t type;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
type = dn->dn_bonustype;
DB_DNODE_EXIT(db);
return (type);
}
int
dmu_rm_spill(objset_t *os, uint64_t object, dmu_tx_t *tx)
{
dnode_t *dn;
int error;
error = dnode_hold(os, object, FTAG, &dn);
dbuf_rm_spill(dn, tx);
rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
dnode_rm_spill(dn, tx);
rw_exit(&dn->dn_struct_rwlock);
dnode_rele(dn, FTAG);
return (error);
}
/*
* returns ENOENT, EIO, or 0.
*/
int
dmu_bonus_hold_impl(objset_t *os, uint64_t object, void *tag, uint32_t flags,
dmu_buf_t **dbp)
{
dnode_t *dn;
dmu_buf_impl_t *db;
int error;
uint32_t db_flags = DB_RF_MUST_SUCCEED;
if (flags & DMU_READ_NO_PREFETCH)
db_flags |= DB_RF_NOPREFETCH;
if (flags & DMU_READ_NO_DECRYPT)
db_flags |= DB_RF_NO_DECRYPT;
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);
error = dbuf_read(db, NULL, db_flags);
if (error) {
dnode_evict_bonus(dn);
dbuf_rele(db, tag);
*dbp = NULL;
return (error);
}
*dbp = &db->db;
return (0);
}
int
dmu_bonus_hold(objset_t *os, uint64_t obj, void *tag, dmu_buf_t **dbp)
{
return (dmu_bonus_hold_impl(os, obj, tag, DMU_READ_NO_PREFETCH, dbp));
}
/*
* returns ENOENT, EIO, or 0.
*
* This interface will allocate a blank spill dbuf when a spill blk
* doesn't already exist on the dnode.
*
* if you only want to find an already existing spill db, then
* dmu_spill_hold_existing() should be used.
*/
int
dmu_spill_hold_by_dnode(dnode_t *dn, uint32_t flags, void *tag, dmu_buf_t **dbp)
{
dmu_buf_impl_t *db = NULL;
int err;
if ((flags & DB_RF_HAVESTRUCT) == 0)
rw_enter(&dn->dn_struct_rwlock, RW_READER);
db = dbuf_hold(dn, DMU_SPILL_BLKID, tag);
if ((flags & DB_RF_HAVESTRUCT) == 0)
rw_exit(&dn->dn_struct_rwlock);
if (db == NULL) {
*dbp = NULL;
return (SET_ERROR(EIO));
}
err = dbuf_read(db, NULL, flags);
if (err == 0)
*dbp = &db->db;
else {
dbuf_rele(db, tag);
*dbp = NULL;
}
return (err);
}
int
dmu_spill_hold_existing(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)bonus;
dnode_t *dn;
int err;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_SA) {
err = SET_ERROR(EINVAL);
} else {
rw_enter(&dn->dn_struct_rwlock, RW_READER);
if (!dn->dn_have_spill) {
err = SET_ERROR(ENOENT);
} else {
err = dmu_spill_hold_by_dnode(dn,
DB_RF_HAVESTRUCT | DB_RF_CANFAIL, tag, dbp);
}
rw_exit(&dn->dn_struct_rwlock);
}
DB_DNODE_EXIT(db);
return (err);
}
int
dmu_spill_hold_by_bonus(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)bonus;
dnode_t *dn;
int err;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
err = dmu_spill_hold_by_dnode(dn, DB_RF_CANFAIL, tag, dbp);
DB_DNODE_EXIT(db);
return (err);
}
/*
* Note: longer-term, we should modify all of the dmu_buf_*() interfaces
* to take a held dnode rather than <os, object> -- the lookup is wasteful,
* and can induce severe lock contention when writing to several files
* whose dnodes are in the same block.
*/
static int
dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset, uint64_t length,
boolean_t read, void *tag, int *numbufsp, dmu_buf_t ***dbpp, uint32_t flags)
{
dmu_buf_t **dbp;
uint64_t blkid, nblks, i;
uint32_t dbuf_flags;
int err;
zio_t *zio;
ASSERT(length <= DMU_MAX_ACCESS);
/*
* Note: We directly notify the prefetch code of this read, so that
* we can tell it about the multi-block read. dbuf_read() only knows
* about the one block it is accessing.
*/
dbuf_flags = DB_RF_CANFAIL | DB_RF_NEVERWAIT | DB_RF_HAVESTRUCT |
DB_RF_NOPREFETCH;
rw_enter(&dn->dn_struct_rwlock, RW_READER);
if (dn->dn_datablkshift) {
int blkshift = dn->dn_datablkshift;
nblks = (P2ROUNDUP(offset + length, 1ULL << blkshift) -
P2ALIGN(offset, 1ULL << blkshift)) >> blkshift;
} else {
if (offset + length > dn->dn_datablksz) {
zfs_panic_recover("zfs: accessing past end of object "
"%llx/%llx (size=%u access=%llu+%llu)",
(longlong_t)dn->dn_objset->
os_dsl_dataset->ds_object,
(longlong_t)dn->dn_object, dn->dn_datablksz,
(longlong_t)offset, (longlong_t)length);
rw_exit(&dn->dn_struct_rwlock);
return (SET_ERROR(EIO));
}
nblks = 1;
}
dbp = kmem_zalloc(sizeof (dmu_buf_t *) * nblks, KM_SLEEP);
zio = zio_root(dn->dn_objset->os_spa, NULL, NULL, ZIO_FLAG_CANFAIL);
blkid = dbuf_whichblock(dn, 0, offset);
for (i = 0; i < nblks; i++) {
dmu_buf_impl_t *db = dbuf_hold(dn, blkid + i, tag);
if (db == NULL) {
rw_exit(&dn->dn_struct_rwlock);
dmu_buf_rele_array(dbp, nblks, tag);
zio_nowait(zio);
return (SET_ERROR(EIO));
}
/* initiate async i/o */
if (read)
(void) dbuf_read(db, zio, dbuf_flags);
dbp[i] = &db->db;
}
if ((flags & DMU_READ_NO_PREFETCH) == 0 &&
DNODE_META_IS_CACHEABLE(dn) && length <= zfetch_array_rd_sz) {
dmu_zfetch(&dn->dn_zfetch, blkid, nblks,
read && DNODE_IS_CACHEABLE(dn));
}
rw_exit(&dn->dn_struct_rwlock);
/* wait for async i/o */
err = zio_wait(zio);
if (err) {
dmu_buf_rele_array(dbp, nblks, tag);
return (err);
}
/* wait for other io to complete */
if (read) {
for (i = 0; i < nblks; i++) {
dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbp[i];
mutex_enter(&db->db_mtx);
while (db->db_state == DB_READ ||
db->db_state == DB_FILL)
cv_wait(&db->db_changed, &db->db_mtx);
if (db->db_state == DB_UNCACHED)
err = SET_ERROR(EIO);
mutex_exit(&db->db_mtx);
if (err) {
dmu_buf_rele_array(dbp, nblks, tag);
return (err);
}
}
}
*numbufsp = nblks;
*dbpp = dbp;
return (0);
}
static int
dmu_buf_hold_array(objset_t *os, uint64_t object, uint64_t offset,
uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
{
dnode_t *dn;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
numbufsp, dbpp, DMU_READ_PREFETCH);
dnode_rele(dn, FTAG);
return (err);
}
int
dmu_buf_hold_array_by_bonus(dmu_buf_t *db_fake, uint64_t offset,
uint64_t length, boolean_t read, void *tag, int *numbufsp,
dmu_buf_t ***dbpp)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
dnode_t *dn;
int err;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
numbufsp, dbpp, DMU_READ_PREFETCH);
DB_DNODE_EXIT(db);
return (err);
}
void
dmu_buf_rele_array(dmu_buf_t **dbp_fake, int numbufs, void *tag)
{
int i;
dmu_buf_impl_t **dbp = (dmu_buf_impl_t **)dbp_fake;
if (numbufs == 0)
return;
for (i = 0; i < numbufs; i++) {
if (dbp[i])
dbuf_rele(dbp[i], tag);
}
kmem_free(dbp, sizeof (dmu_buf_t *) * numbufs);
}
/*
* Issue prefetch i/os for the given blocks. If level is greater than 0, the
* indirect blocks prefeteched will be those that point to the blocks containing
* the data starting at offset, and continuing to offset + len.
*
* Note that if the indirect blocks above the blocks being prefetched are not
* in cache, they will be asychronously read in.
*/
void
dmu_prefetch(objset_t *os, uint64_t object, int64_t level, uint64_t offset,
uint64_t len, zio_priority_t pri)
{
dnode_t *dn;
uint64_t blkid;
int nblks, err;
if (len == 0) { /* they're interested in the bonus buffer */
dn = DMU_META_DNODE(os);
if (object == 0 || object >= DN_MAX_OBJECT)
return;
rw_enter(&dn->dn_struct_rwlock, RW_READER);
blkid = dbuf_whichblock(dn, level,
object * sizeof (dnode_phys_t));
dbuf_prefetch(dn, level, blkid, pri, 0);
rw_exit(&dn->dn_struct_rwlock);
return;
}
/*
* XXX - Note, if the dnode for the requested object is not
* already cached, we will do a *synchronous* read in the
* dnode_hold() call. The same is true for any indirects.
*/
err = dnode_hold(os, object, FTAG, &dn);
if (err != 0)
return;
rw_enter(&dn->dn_struct_rwlock, RW_READER);
/*
* offset + len - 1 is the last byte we want to prefetch for, and offset
* is the first. Then dbuf_whichblk(dn, level, off + len - 1) is the
* last block we want to prefetch, and dbuf_whichblock(dn, level,
* offset) is the first. Then the number we need to prefetch is the
* last - first + 1.
*/
if (level > 0 || dn->dn_datablkshift != 0) {
nblks = dbuf_whichblock(dn, level, offset + len - 1) -
dbuf_whichblock(dn, level, offset) + 1;
} else {
nblks = (offset < dn->dn_datablksz);
}
if (nblks != 0) {
blkid = dbuf_whichblock(dn, level, offset);
for (int i = 0; i < nblks; i++)
dbuf_prefetch(dn, level, blkid + i, pri, 0);
}
rw_exit(&dn->dn_struct_rwlock);
dnode_rele(dn, FTAG);
}
/*
* Get the next "chunk" of file data to free. We traverse the file from
* the end so that the file gets shorter over time (if we crashes in the
* middle, this will leave us in a better state). We find allocated file
* data by simply searching the allocated level 1 indirects.
*
* On input, *start should be the first offset that does not need to be
* freed (e.g. "offset + length"). On return, *start will be the first
* offset that should be freed.
*/
static int
get_next_chunk(dnode_t *dn, uint64_t *start, uint64_t minimum)
{
uint64_t maxblks = DMU_MAX_ACCESS >> (dn->dn_indblkshift + 1);
/* bytes of data covered by a level-1 indirect block */
uint64_t iblkrange =
dn->dn_datablksz * EPB(dn->dn_indblkshift, SPA_BLKPTRSHIFT);
ASSERT3U(minimum, <=, *start);
if (*start - minimum <= iblkrange * maxblks) {
*start = minimum;
return (0);
}
ASSERT(ISP2(iblkrange));
for (uint64_t blks = 0; *start > minimum && blks < maxblks; blks++) {
int err;
/*
* dnode_next_offset(BACKWARDS) will find an allocated L1
* indirect block at or before the input offset. We must
* decrement *start so that it is at the end of the region
* to search.
*/
(*start)--;
err = dnode_next_offset(dn,
DNODE_FIND_BACKWARDS, start, 2, 1, 0);
/* if there are no indirect blocks before start, we are done */
if (err == ESRCH) {
*start = minimum;
break;
} else if (err != 0) {
return (err);
}
/* set start to the beginning of this L1 indirect */
*start = P2ALIGN(*start, iblkrange);
}
if (*start < minimum)
*start = minimum;
return (0);
}
/*
* If this objset is of type OST_ZFS return true if vfs's unmounted flag is set,
* otherwise return false.
* Used below in dmu_free_long_range_impl() to enable abort when unmounting
*/
/*ARGSUSED*/
static boolean_t
dmu_objset_zfs_unmounting(objset_t *os)
{
#ifdef _KERNEL
if (dmu_objset_type(os) == DMU_OST_ZFS)
return (zfs_get_vfs_flag_unmounted(os));
#endif
return (B_FALSE);
}
static int
dmu_free_long_range_impl(objset_t *os, dnode_t *dn, uint64_t offset,
uint64_t length, boolean_t raw)
{
uint64_t object_size;
int err;
uint64_t dirty_frees_threshold;
dsl_pool_t *dp = dmu_objset_pool(os);
if (dn == NULL)
return (SET_ERROR(EINVAL));
object_size = (dn->dn_maxblkid + 1) * dn->dn_datablksz;
if (offset >= object_size)
return (0);
if (zfs_per_txg_dirty_frees_percent <= 100)
dirty_frees_threshold =
zfs_per_txg_dirty_frees_percent * zfs_dirty_data_max / 100;
else
dirty_frees_threshold = zfs_dirty_data_max / 4;
if (length == DMU_OBJECT_END || offset + length > object_size)
length = object_size - offset;
while (length != 0) {
uint64_t chunk_end, chunk_begin, chunk_len;
uint64_t long_free_dirty_all_txgs = 0;
dmu_tx_t *tx;
if (dmu_objset_zfs_unmounting(dn->dn_objset))
return (SET_ERROR(EINTR));
chunk_end = chunk_begin = offset + length;
/* move chunk_begin backwards to the beginning of this chunk */
err = get_next_chunk(dn, &chunk_begin, offset);
if (err)
return (err);
ASSERT3U(chunk_begin, >=, offset);
ASSERT3U(chunk_begin, <=, chunk_end);
chunk_len = chunk_end - chunk_begin;
mutex_enter(&dp->dp_lock);
for (int t = 0; t < TXG_SIZE; t++) {
long_free_dirty_all_txgs +=
dp->dp_long_free_dirty_pertxg[t];
}
mutex_exit(&dp->dp_lock);
/*
* To avoid filling up a TXG with just frees wait for
* the next TXG to open before freeing more chunks if
* we have reached the threshold of frees
*/
if (dirty_frees_threshold != 0 &&
long_free_dirty_all_txgs >= dirty_frees_threshold) {
txg_wait_open(dp, 0);
continue;
}
tx = dmu_tx_create(os);
dmu_tx_hold_free(tx, dn->dn_object, chunk_begin, chunk_len);
/*
* Mark this transaction as typically resulting in a net
* reduction in space used.
*/
dmu_tx_mark_netfree(tx);
err = dmu_tx_assign(tx, TXG_WAIT);
if (err) {
dmu_tx_abort(tx);
return (err);
}
mutex_enter(&dp->dp_lock);
dp->dp_long_free_dirty_pertxg[dmu_tx_get_txg(tx) & TXG_MASK] +=
chunk_len;
mutex_exit(&dp->dp_lock);
DTRACE_PROBE3(free__long__range,
uint64_t, long_free_dirty_all_txgs, uint64_t, chunk_len,
uint64_t, dmu_tx_get_txg(tx));
dnode_free_range(dn, chunk_begin, chunk_len, tx);
/* if this is a raw free, mark the dirty record as such */
if (raw) {
dbuf_dirty_record_t *dr = dn->dn_dbuf->db_last_dirty;
while (dr != NULL && dr->dr_txg > tx->tx_txg)
dr = dr->dr_next;
if (dr != NULL && dr->dr_txg == tx->tx_txg)
dr->dt.dl.dr_raw = B_TRUE;
}
dmu_tx_commit(tx);
length -= chunk_len;
}
return (0);
}
int
dmu_free_long_range(objset_t *os, uint64_t object,
uint64_t offset, uint64_t length)
{
dnode_t *dn;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err != 0)
return (err);
err = dmu_free_long_range_impl(os, dn, offset, length, B_FALSE);
/*
* It is important to zero out the maxblkid when freeing the entire
* file, so that (a) subsequent calls to dmu_free_long_range_impl()
* will take the fast path, and (b) dnode_reallocate() can verify
* that the entire file has been freed.
*/
if (err == 0 && offset == 0 && length == DMU_OBJECT_END)
dn->dn_maxblkid = 0;
dnode_rele(dn, FTAG);
return (err);
}
/*
* This function is equivalent to dmu_free_long_range(), but also
* marks the new dirty record as a raw write.
*/
int
dmu_free_long_range_raw(objset_t *os, uint64_t object,
uint64_t offset, uint64_t length)
{
dnode_t *dn;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err != 0)
return (err);
err = dmu_free_long_range_impl(os, dn, offset, length, B_TRUE);
/*
* It is important to zero out the maxblkid when freeing the entire
* file, so that (a) subsequent calls to dmu_free_long_range_impl()
* will take the fast path, and (b) dnode_reallocate() can verify
* that the entire file has been freed.
*/
if (err == 0 && offset == 0 && length == DMU_OBJECT_END)
dn->dn_maxblkid = 0;
dnode_rele(dn, FTAG);
return (err);
}
static int
dmu_free_long_object_impl(objset_t *os, uint64_t object, boolean_t raw)
{
dmu_tx_t *tx;
int err;
err = dmu_free_long_range(os, object, 0, DMU_OBJECT_END);
if (err != 0)
return (err);
tx = dmu_tx_create(os);
dmu_tx_hold_bonus(tx, object);
dmu_tx_hold_free(tx, object, 0, DMU_OBJECT_END);
dmu_tx_mark_netfree(tx);
err = dmu_tx_assign(tx, TXG_WAIT);
if (err == 0) {
if (raw)
err = dmu_object_dirty_raw(os, object, tx);
if (err == 0)
err = dmu_object_free(os, object, tx);
dmu_tx_commit(tx);
} else {
dmu_tx_abort(tx);
}
return (err);
}
int
dmu_free_long_object(objset_t *os, uint64_t object)
{
return (dmu_free_long_object_impl(os, object, B_FALSE));
}
int
dmu_free_long_object_raw(objset_t *os, uint64_t object)
{
return (dmu_free_long_object_impl(os, object, B_TRUE));
}
int
dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
uint64_t size, dmu_tx_t *tx)
{
dnode_t *dn;
int err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
ASSERT(offset < UINT64_MAX);
ASSERT(size == DMU_OBJECT_END || size <= UINT64_MAX - offset);
dnode_free_range(dn, offset, size, tx);
dnode_rele(dn, FTAG);
return (0);
}
static int
dmu_read_impl(dnode_t *dn, uint64_t offset, uint64_t size,
void *buf, uint32_t flags)
{
dmu_buf_t **dbp;
int numbufs, err = 0;
/*
* Deal with odd block sizes, where there can't be data past the first
* block. If we ever do the tail block optimization, we will need to
* handle that here as well.
*/
if (dn->dn_maxblkid == 0) {
uint64_t newsz = offset > dn->dn_datablksz ? 0 :
MIN(size, dn->dn_datablksz - offset);
bzero((char *)buf + newsz, size - newsz);
size = newsz;
}
while (size > 0) {
uint64_t mylen = MIN(size, DMU_MAX_ACCESS / 2);
int i;
/*
* NB: we could do this block-at-a-time, but it's nice
* to be reading in parallel.
*/
err = dmu_buf_hold_array_by_dnode(dn, offset, mylen,
TRUE, FTAG, &numbufs, &dbp, flags);
if (err)
break;
for (i = 0; i < numbufs; i++) {
uint64_t tocpy;
int64_t bufoff;
dmu_buf_t *db = dbp[i];
ASSERT(size > 0);
bufoff = offset - db->db_offset;
tocpy = MIN(db->db_size - bufoff, size);
(void) memcpy(buf, (char *)db->db_data + bufoff, tocpy);
offset += tocpy;
size -= tocpy;
buf = (char *)buf + tocpy;
}
dmu_buf_rele_array(dbp, numbufs, FTAG);
}
return (err);
}
int
dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
void *buf, uint32_t flags)
{
dnode_t *dn;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err != 0)
return (err);
err = dmu_read_impl(dn, offset, size, buf, flags);
dnode_rele(dn, FTAG);
return (err);
}
int
dmu_read_by_dnode(dnode_t *dn, uint64_t offset, uint64_t size, void *buf,
uint32_t flags)
{
return (dmu_read_impl(dn, offset, size, buf, flags));
}
static void
dmu_write_impl(dmu_buf_t **dbp, int numbufs, uint64_t offset, uint64_t size,
const void *buf, dmu_tx_t *tx)
{
int i;
for (i = 0; i < numbufs; i++) {
uint64_t tocpy;
int64_t bufoff;
dmu_buf_t *db = dbp[i];
ASSERT(size > 0);
bufoff = offset - db->db_offset;
tocpy = MIN(db->db_size - bufoff, size);
ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
if (tocpy == db->db_size)
dmu_buf_will_fill(db, tx);
else
dmu_buf_will_dirty(db, tx);
(void) memcpy((char *)db->db_data + bufoff, buf, tocpy);
if (tocpy == db->db_size)
dmu_buf_fill_done(db, tx);
offset += tocpy;
size -= tocpy;
buf = (char *)buf + tocpy;
}
}
void
dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
const void *buf, dmu_tx_t *tx)
{
dmu_buf_t **dbp;
int numbufs;
if (size == 0)
return;
VERIFY0(dmu_buf_hold_array(os, object, offset, size,
FALSE, FTAG, &numbufs, &dbp));
dmu_write_impl(dbp, numbufs, offset, size, buf, tx);
dmu_buf_rele_array(dbp, numbufs, FTAG);
}
void
dmu_write_by_dnode(dnode_t *dn, uint64_t offset, uint64_t size,
const void *buf, dmu_tx_t *tx)
{
dmu_buf_t **dbp;
int numbufs;
if (size == 0)
return;
VERIFY0(dmu_buf_hold_array_by_dnode(dn, offset, size,
FALSE, FTAG, &numbufs, &dbp, DMU_READ_PREFETCH));
dmu_write_impl(dbp, numbufs, offset, size, buf, tx);
dmu_buf_rele_array(dbp, numbufs, FTAG);
}
void
dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
dmu_tx_t *tx)
{
dmu_buf_t **dbp;
int numbufs, i;
if (size == 0)
return;
VERIFY(0 == dmu_buf_hold_array(os, object, offset, size,
FALSE, FTAG, &numbufs, &dbp));
for (i = 0; i < numbufs; i++) {
dmu_buf_t *db = dbp[i];
dmu_buf_will_not_fill(db, tx);
}
dmu_buf_rele_array(dbp, numbufs, FTAG);
}
void
dmu_write_embedded(objset_t *os, uint64_t object, uint64_t offset,
void *data, uint8_t etype, uint8_t comp, int uncompressed_size,
int compressed_size, int byteorder, dmu_tx_t *tx)
{
dmu_buf_t *db;
ASSERT3U(etype, <, NUM_BP_EMBEDDED_TYPES);
ASSERT3U(comp, <, ZIO_COMPRESS_FUNCTIONS);
VERIFY0(dmu_buf_hold_noread(os, object, offset,
FTAG, &db));
dmu_buf_write_embedded(db,
data, (bp_embedded_type_t)etype, (enum zio_compress)comp,
uncompressed_size, compressed_size, byteorder, tx);
dmu_buf_rele(db, FTAG);
}
/*
* DMU support for xuio
*/
kstat_t *xuio_ksp = NULL;
typedef struct xuio_stats {
/* loaned yet not returned arc_buf */
kstat_named_t xuiostat_onloan_rbuf;
kstat_named_t xuiostat_onloan_wbuf;
/* whether a copy is made when loaning out a read buffer */
kstat_named_t xuiostat_rbuf_copied;
kstat_named_t xuiostat_rbuf_nocopy;
/* whether a copy is made when assigning a write buffer */
kstat_named_t xuiostat_wbuf_copied;
kstat_named_t xuiostat_wbuf_nocopy;
} xuio_stats_t;
static xuio_stats_t xuio_stats = {
{ "onloan_read_buf", KSTAT_DATA_UINT64 },
{ "onloan_write_buf", KSTAT_DATA_UINT64 },
{ "read_buf_copied", KSTAT_DATA_UINT64 },
{ "read_buf_nocopy", KSTAT_DATA_UINT64 },
{ "write_buf_copied", KSTAT_DATA_UINT64 },
{ "write_buf_nocopy", KSTAT_DATA_UINT64 }
};
#define XUIOSTAT_INCR(stat, val) \
atomic_add_64(&xuio_stats.stat.value.ui64, (val))
#define XUIOSTAT_BUMP(stat) XUIOSTAT_INCR(stat, 1)
#ifdef HAVE_UIO_ZEROCOPY
int
dmu_xuio_init(xuio_t *xuio, int nblk)
{
dmu_xuio_t *priv;
uio_t *uio = &xuio->xu_uio;
uio->uio_iovcnt = nblk;
uio->uio_iov = kmem_zalloc(nblk * sizeof (iovec_t), KM_SLEEP);
priv = kmem_zalloc(sizeof (dmu_xuio_t), KM_SLEEP);
priv->cnt = nblk;
priv->bufs = kmem_zalloc(nblk * sizeof (arc_buf_t *), KM_SLEEP);
priv->iovp = (iovec_t *)uio->uio_iov;
XUIO_XUZC_PRIV(xuio) = priv;
if (XUIO_XUZC_RW(xuio) == UIO_READ)
XUIOSTAT_INCR(xuiostat_onloan_rbuf, nblk);
else
XUIOSTAT_INCR(xuiostat_onloan_wbuf, nblk);
return (0);
}
void
dmu_xuio_fini(xuio_t *xuio)
{
dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
int nblk = priv->cnt;
kmem_free(priv->iovp, nblk * sizeof (iovec_t));
kmem_free(priv->bufs, nblk * sizeof (arc_buf_t *));
kmem_free(priv, sizeof (dmu_xuio_t));
if (XUIO_XUZC_RW(xuio) == UIO_READ)
XUIOSTAT_INCR(xuiostat_onloan_rbuf, -nblk);
else
XUIOSTAT_INCR(xuiostat_onloan_wbuf, -nblk);
}
/*
* Initialize iov[priv->next] and priv->bufs[priv->next] with { off, n, abuf }
* and increase priv->next by 1.
*/
int
dmu_xuio_add(xuio_t *xuio, arc_buf_t *abuf, offset_t off, size_t n)
{
struct iovec *iov;
uio_t *uio = &xuio->xu_uio;
dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
int i = priv->next++;
ASSERT(i < priv->cnt);
ASSERT(off + n <= arc_buf_lsize(abuf));
iov = (iovec_t *)uio->uio_iov + i;
iov->iov_base = (char *)abuf->b_data + off;
iov->iov_len = n;
priv->bufs[i] = abuf;
return (0);
}
int
dmu_xuio_cnt(xuio_t *xuio)
{
dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
return (priv->cnt);
}
arc_buf_t *
dmu_xuio_arcbuf(xuio_t *xuio, int i)
{
dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
ASSERT(i < priv->cnt);
return (priv->bufs[i]);
}
void
dmu_xuio_clear(xuio_t *xuio, int i)
{
dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
ASSERT(i < priv->cnt);
priv->bufs[i] = NULL;
}
#endif /* HAVE_UIO_ZEROCOPY */
static void
xuio_stat_init(void)
{
xuio_ksp = kstat_create("zfs", 0, "xuio_stats", "misc",
KSTAT_TYPE_NAMED, sizeof (xuio_stats) / sizeof (kstat_named_t),
KSTAT_FLAG_VIRTUAL);
if (xuio_ksp != NULL) {
xuio_ksp->ks_data = &xuio_stats;
kstat_install(xuio_ksp);
}
}
static void
xuio_stat_fini(void)
{
if (xuio_ksp != NULL) {
kstat_delete(xuio_ksp);
xuio_ksp = NULL;
}
}
void
xuio_stat_wbuf_copied(void)
{
XUIOSTAT_BUMP(xuiostat_wbuf_copied);
}
void
xuio_stat_wbuf_nocopy(void)
{
XUIOSTAT_BUMP(xuiostat_wbuf_nocopy);
}
#ifdef _KERNEL
int
dmu_read_uio_dnode(dnode_t *dn, uio_t *uio, uint64_t size)
{
dmu_buf_t **dbp;
int numbufs, i, err;
#ifdef HAVE_UIO_ZEROCOPY
xuio_t *xuio = NULL;
#endif
/*
* NB: we could do this block-at-a-time, but it's nice
* to be reading in parallel.
*/
err = dmu_buf_hold_array_by_dnode(dn, uio->uio_loffset, size,
TRUE, FTAG, &numbufs, &dbp, 0);
if (err)
return (err);
for (i = 0; i < numbufs; i++) {
uint64_t tocpy;
int64_t bufoff;
dmu_buf_t *db = dbp[i];
ASSERT(size > 0);
bufoff = uio->uio_loffset - db->db_offset;
tocpy = MIN(db->db_size - bufoff, size);
#ifdef HAVE_UIO_ZEROCOPY
if (xuio) {
dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
arc_buf_t *dbuf_abuf = dbi->db_buf;
arc_buf_t *abuf = dbuf_loan_arcbuf(dbi);
err = dmu_xuio_add(xuio, abuf, bufoff, tocpy);
if (!err) {
uio->uio_resid -= tocpy;
uio->uio_loffset += tocpy;
}
if (abuf == dbuf_abuf)
XUIOSTAT_BUMP(xuiostat_rbuf_nocopy);
else
XUIOSTAT_BUMP(xuiostat_rbuf_copied);
} else
#endif
err = uiomove((char *)db->db_data + bufoff, tocpy,
UIO_READ, uio);
if (err)
break;
size -= tocpy;
}
dmu_buf_rele_array(dbp, numbufs, FTAG);
return (err);
}
/*
* Read 'size' bytes into the uio buffer.
* From object zdb->db_object.
* Starting at offset uio->uio_loffset.
*
* If the caller already has a dbuf in the target object
* (e.g. its bonus buffer), this routine is faster than dmu_read_uio(),
* because we don't have to find the dnode_t for the object.
*/
int
dmu_read_uio_dbuf(dmu_buf_t *zdb, uio_t *uio, uint64_t size)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)zdb;
dnode_t *dn;
int err;
if (size == 0)
return (0);
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
err = dmu_read_uio_dnode(dn, uio, size);
DB_DNODE_EXIT(db);
return (err);
}
/*
* Read 'size' bytes into the uio buffer.
* From the specified object
* Starting at offset uio->uio_loffset.
*/
int
dmu_read_uio(objset_t *os, uint64_t object, uio_t *uio, uint64_t size)
{
dnode_t *dn;
int err;
if (size == 0)
return (0);
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
err = dmu_read_uio_dnode(dn, uio, size);
dnode_rele(dn, FTAG);
return (err);
}
int
dmu_write_uio_dnode(dnode_t *dn, uio_t *uio, uint64_t size, dmu_tx_t *tx)
{
dmu_buf_t **dbp;
int numbufs;
int err = 0;
int i;
err = dmu_buf_hold_array_by_dnode(dn, uio->uio_loffset, size,
FALSE, FTAG, &numbufs, &dbp, DMU_READ_PREFETCH);
if (err)
return (err);
for (i = 0; i < numbufs; i++) {
uint64_t tocpy;
int64_t bufoff;
dmu_buf_t *db = dbp[i];
ASSERT(size > 0);
bufoff = uio->uio_loffset - db->db_offset;
tocpy = MIN(db->db_size - bufoff, size);
ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
if (tocpy == db->db_size)
dmu_buf_will_fill(db, tx);
else
dmu_buf_will_dirty(db, tx);
/*
* XXX uiomove could block forever (eg.nfs-backed
* pages). There needs to be a uiolockdown() function
* to lock the pages in memory, so that uiomove won't
* block.
*/
err = uiomove((char *)db->db_data + bufoff, tocpy,
UIO_WRITE, uio);
if (tocpy == db->db_size)
dmu_buf_fill_done(db, tx);
if (err)
break;
size -= tocpy;
}
dmu_buf_rele_array(dbp, numbufs, FTAG);
return (err);
}
/*
* Write 'size' bytes from the uio buffer.
* To object zdb->db_object.
* Starting at offset uio->uio_loffset.
*
* If the caller already has a dbuf in the target object
* (e.g. its bonus buffer), this routine is faster than dmu_write_uio(),
* because we don't have to find the dnode_t for the object.
*/
int
dmu_write_uio_dbuf(dmu_buf_t *zdb, uio_t *uio, uint64_t size,
dmu_tx_t *tx)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)zdb;
dnode_t *dn;
int err;
if (size == 0)
return (0);
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
err = dmu_write_uio_dnode(dn, uio, size, tx);
DB_DNODE_EXIT(db);
return (err);
}
/*
* Write 'size' bytes from the uio buffer.
* To the specified object.
* Starting at offset uio->uio_loffset.
*/
int
dmu_write_uio(objset_t *os, uint64_t object, uio_t *uio, uint64_t size,
dmu_tx_t *tx)
{
dnode_t *dn;
int err;
if (size == 0)
return (0);
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
err = dmu_write_uio_dnode(dn, uio, size, tx);
dnode_rele(dn, FTAG);
return (err);
}
#endif /* _KERNEL */
/*
* Allocate a loaned anonymous arc buffer.
*/
arc_buf_t *
dmu_request_arcbuf(dmu_buf_t *handle, int size)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)handle;
return (arc_loan_buf(db->db_objset->os_spa, B_FALSE, size));
}
/*
* Free a loaned arc buffer.
*/
void
dmu_return_arcbuf(arc_buf_t *buf)
{
arc_return_buf(buf, FTAG);
arc_buf_destroy(buf, FTAG);
}
void
dmu_convert_to_raw(dmu_buf_t *handle, boolean_t byteorder, const uint8_t *salt,
const uint8_t *iv, const uint8_t *mac, dmu_tx_t *tx)
{
dmu_object_type_t type;
dmu_buf_impl_t *db = (dmu_buf_impl_t *)handle;
uint64_t dsobj = dmu_objset_id(db->db_objset);
ASSERT3P(db->db_buf, !=, NULL);
ASSERT3U(dsobj, !=, 0);
dmu_buf_will_change_crypt_params(handle, tx);
DB_DNODE_ENTER(db);
type = DB_DNODE(db)->dn_type;
DB_DNODE_EXIT(db);
/*
* This technically violates the assumption the dmu code makes
* that dnode blocks are only released in syncing context.
*/
(void) arc_release(db->db_buf, db);
arc_convert_to_raw(db->db_buf, dsobj, byteorder, type, salt, iv, mac);
}
void
dmu_copy_from_buf(objset_t *os, uint64_t object, uint64_t offset,
dmu_buf_t *handle, dmu_tx_t *tx)
{
dmu_buf_t *dst_handle;
dmu_buf_impl_t *dstdb;
dmu_buf_impl_t *srcdb = (dmu_buf_impl_t *)handle;
arc_buf_t *abuf;
uint64_t datalen;
boolean_t byteorder;
uint8_t salt[ZIO_DATA_SALT_LEN];
uint8_t iv[ZIO_DATA_IV_LEN];
uint8_t mac[ZIO_DATA_MAC_LEN];
ASSERT3P(srcdb->db_buf, !=, NULL);
/* hold the db that we want to write to */
VERIFY0(dmu_buf_hold(os, object, offset, FTAG, &dst_handle,
DMU_READ_NO_DECRYPT));
dstdb = (dmu_buf_impl_t *)dst_handle;
datalen = arc_buf_size(srcdb->db_buf);
/* allocated an arc buffer that matches the type of srcdb->db_buf */
if (arc_is_encrypted(srcdb->db_buf)) {
arc_get_raw_params(srcdb->db_buf, &byteorder, salt, iv, mac);
abuf = arc_loan_raw_buf(os->os_spa, dmu_objset_id(os),
byteorder, salt, iv, mac, DB_DNODE(dstdb)->dn_type,
datalen, arc_buf_lsize(srcdb->db_buf),
arc_get_compression(srcdb->db_buf));
} else {
/* we won't get a compressed db back from dmu_buf_hold() */
ASSERT3U(arc_get_compression(srcdb->db_buf),
==, ZIO_COMPRESS_OFF);
abuf = arc_loan_buf(os->os_spa,
DMU_OT_IS_METADATA(DB_DNODE(dstdb)->dn_type), datalen);
}
ASSERT3U(datalen, ==, arc_buf_size(abuf));
/* copy the data to the new buffer and assign it to the dstdb */
bcopy(srcdb->db_buf->b_data, abuf->b_data, datalen);
dbuf_assign_arcbuf(dstdb, abuf, tx);
dmu_buf_rele(dst_handle, FTAG);
}
/*
* When possible directly assign passed loaned arc buffer to a dbuf.
* If this is not possible copy the contents of passed arc buf via
* dmu_write().
*/
void
dmu_assign_arcbuf_by_dnode(dnode_t *dn, uint64_t offset, arc_buf_t *buf,
dmu_tx_t *tx)
{
dmu_buf_impl_t *db;
objset_t *os = dn->dn_objset;
uint64_t object = dn->dn_object;
uint32_t blksz = (uint32_t)arc_buf_lsize(buf);
uint64_t blkid;
rw_enter(&dn->dn_struct_rwlock, RW_READER);
blkid = dbuf_whichblock(dn, 0, offset);
VERIFY((db = dbuf_hold(dn, blkid, FTAG)) != NULL);
rw_exit(&dn->dn_struct_rwlock);
/*
* We can only assign if the offset is aligned, the arc buf is the
* same size as the dbuf, and the dbuf is not metadata.
*/
if (offset == db->db.db_offset && blksz == db->db.db_size) {
dbuf_assign_arcbuf(db, buf, tx);
dbuf_rele(db, FTAG);
} else {
/* compressed bufs must always be assignable to their dbuf */
ASSERT3U(arc_get_compression(buf), ==, ZIO_COMPRESS_OFF);
ASSERT(!(buf->b_flags & ARC_BUF_FLAG_COMPRESSED));
dbuf_rele(db, FTAG);
dmu_write(os, object, offset, blksz, buf->b_data, tx);
dmu_return_arcbuf(buf);
XUIOSTAT_BUMP(xuiostat_wbuf_copied);
}
}
void
dmu_assign_arcbuf_by_dbuf(dmu_buf_t *handle, uint64_t offset, arc_buf_t *buf,
dmu_tx_t *tx)
{
dmu_buf_impl_t *dbuf = (dmu_buf_impl_t *)handle;
DB_DNODE_ENTER(dbuf);
dmu_assign_arcbuf_by_dnode(DB_DNODE(dbuf), offset, buf, tx);
DB_DNODE_EXIT(dbuf);
}
typedef struct {
dbuf_dirty_record_t *dsa_dr;
dmu_sync_cb_t *dsa_done;
zgd_t *dsa_zgd;
dmu_tx_t *dsa_tx;
} dmu_sync_arg_t;
/* ARGSUSED */
static void
dmu_sync_ready(zio_t *zio, arc_buf_t *buf, void *varg)
{
dmu_sync_arg_t *dsa = varg;
dmu_buf_t *db = dsa->dsa_zgd->zgd_db;
blkptr_t *bp = zio->io_bp;
if (zio->io_error == 0) {
if (BP_IS_HOLE(bp)) {
/*
* A block of zeros may compress to a hole, but the
* block size still needs to be known for replay.
*/
BP_SET_LSIZE(bp, db->db_size);
} else if (!BP_IS_EMBEDDED(bp)) {
ASSERT(BP_GET_LEVEL(bp) == 0);
BP_SET_FILL(bp, 1);
}
}
}
static void
dmu_sync_late_arrival_ready(zio_t *zio)
{
dmu_sync_ready(zio, NULL, zio->io_private);
}
/* ARGSUSED */
static void
dmu_sync_done(zio_t *zio, arc_buf_t *buf, void *varg)
{
dmu_sync_arg_t *dsa = varg;
dbuf_dirty_record_t *dr = dsa->dsa_dr;
dmu_buf_impl_t *db = dr->dr_dbuf;
mutex_enter(&db->db_mtx);
ASSERT(dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC);
if (zio->io_error == 0) {
dr->dt.dl.dr_nopwrite = !!(zio->io_flags & ZIO_FLAG_NOPWRITE);
if (dr->dt.dl.dr_nopwrite) {
blkptr_t *bp = zio->io_bp;
blkptr_t *bp_orig = &zio->io_bp_orig;
uint8_t chksum = BP_GET_CHECKSUM(bp_orig);
ASSERT(BP_EQUAL(bp, bp_orig));
VERIFY(BP_EQUAL(bp, db->db_blkptr));
ASSERT(zio->io_prop.zp_compress != ZIO_COMPRESS_OFF);
VERIFY(zio_checksum_table[chksum].ci_flags &
ZCHECKSUM_FLAG_NOPWRITE);
}
dr->dt.dl.dr_overridden_by = *zio->io_bp;
dr->dt.dl.dr_override_state = DR_OVERRIDDEN;
dr->dt.dl.dr_copies = zio->io_prop.zp_copies;
/*
* Old style holes are filled with all zeros, whereas
* new-style holes maintain their lsize, type, level,
* and birth time (see zio_write_compress). While we
* need to reset the BP_SET_LSIZE() call that happened
* in dmu_sync_ready for old style holes, we do *not*
* want to wipe out the information contained in new
* style holes. Thus, only zero out the block pointer if
* it's an old style hole.
*/
if (BP_IS_HOLE(&dr->dt.dl.dr_overridden_by) &&
dr->dt.dl.dr_overridden_by.blk_birth == 0)
BP_ZERO(&dr->dt.dl.dr_overridden_by);
} else {
dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
}
cv_broadcast(&db->db_changed);
mutex_exit(&db->db_mtx);
dsa->dsa_done(dsa->dsa_zgd, zio->io_error);
kmem_free(dsa, sizeof (*dsa));
}
static void
dmu_sync_late_arrival_done(zio_t *zio)
{
blkptr_t *bp = zio->io_bp;
dmu_sync_arg_t *dsa = zio->io_private;
ASSERTV(blkptr_t *bp_orig = &zio->io_bp_orig);
if (zio->io_error == 0 && !BP_IS_HOLE(bp)) {
ASSERT(!(zio->io_flags & ZIO_FLAG_NOPWRITE));
ASSERT(BP_IS_HOLE(bp_orig) || !BP_EQUAL(bp, bp_orig));
ASSERT(zio->io_bp->blk_birth == zio->io_txg);
ASSERT(zio->io_txg > spa_syncing_txg(zio->io_spa));
zio_free(zio->io_spa, zio->io_txg, zio->io_bp);
}
dmu_tx_commit(dsa->dsa_tx);
dsa->dsa_done(dsa->dsa_zgd, zio->io_error);
abd_put(zio->io_abd);
kmem_free(dsa, sizeof (*dsa));
}
static int
dmu_sync_late_arrival(zio_t *pio, objset_t *os, dmu_sync_cb_t *done, zgd_t *zgd,
zio_prop_t *zp, zbookmark_phys_t *zb)
{
dmu_sync_arg_t *dsa;
dmu_tx_t *tx;
tx = dmu_tx_create(os);
dmu_tx_hold_space(tx, zgd->zgd_db->db_size);
if (dmu_tx_assign(tx, TXG_WAIT) != 0) {
dmu_tx_abort(tx);
/* Make zl_get_data do txg_waited_synced() */
return (SET_ERROR(EIO));
}
/*
* In order to prevent the zgd's lwb from being free'd prior to
* dmu_sync_late_arrival_done() being called, we have to ensure
* the lwb's "max txg" takes this tx's txg into account.
*/
zil_lwb_add_txg(zgd->zgd_lwb, dmu_tx_get_txg(tx));
dsa = kmem_alloc(sizeof (dmu_sync_arg_t), KM_SLEEP);
dsa->dsa_dr = NULL;
dsa->dsa_done = done;
dsa->dsa_zgd = zgd;
dsa->dsa_tx = tx;
/*
* Since we are currently syncing this txg, it's nontrivial to
* determine what BP to nopwrite against, so we disable nopwrite.
*
* When syncing, the db_blkptr is initially the BP of the previous
* txg. We can not nopwrite against it because it will be changed
* (this is similar to the non-late-arrival case where the dbuf is
* dirty in a future txg).
*
* Then dbuf_write_ready() sets bp_blkptr to the location we will write.
* We can not nopwrite against it because although the BP will not
* (typically) be changed, the data has not yet been persisted to this
* location.
*
* Finally, when dbuf_write_done() is called, it is theoretically
* possible to always nopwrite, because the data that was written in
* this txg is the same data that we are trying to write. However we
* would need to check that this dbuf is not dirty in any future
* txg's (as we do in the normal dmu_sync() path). For simplicity, we
* don't nopwrite in this case.
*/
zp->zp_nopwrite = B_FALSE;
zio_nowait(zio_write(pio, os->os_spa, dmu_tx_get_txg(tx), zgd->zgd_bp,
abd_get_from_buf(zgd->zgd_db->db_data, zgd->zgd_db->db_size),
zgd->zgd_db->db_size, zgd->zgd_db->db_size, zp,
dmu_sync_late_arrival_ready, NULL, NULL, dmu_sync_late_arrival_done,
dsa, ZIO_PRIORITY_SYNC_WRITE, ZIO_FLAG_CANFAIL, zb));
return (0);
}
/*
* Intent log support: sync the block associated with db to disk.
* N.B. and XXX: the caller is responsible for making sure that the
* data isn't changing while dmu_sync() is writing it.
*
* Return values:
*
* EEXIST: this txg has already been synced, so there's nothing to do.
* The caller should not log the write.
*
* ENOENT: the block was dbuf_free_range()'d, so there's nothing to do.
* The caller should not log the write.
*
* EALREADY: this block is already in the process of being synced.
* The caller should track its progress (somehow).
*
* EIO: could not do the I/O.
* The caller should do a txg_wait_synced().
*
* 0: the I/O has been initiated.
* The caller should log this blkptr in the done callback.
* It is possible that the I/O will fail, in which case
* the error will be reported to the done callback and
* propagated to pio from zio_done().
*/
int
dmu_sync(zio_t *pio, uint64_t txg, dmu_sync_cb_t *done, zgd_t *zgd)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)zgd->zgd_db;
objset_t *os = db->db_objset;
dsl_dataset_t *ds = os->os_dsl_dataset;
dbuf_dirty_record_t *dr;
dmu_sync_arg_t *dsa;
zbookmark_phys_t zb;
zio_prop_t zp;
dnode_t *dn;
ASSERT(pio != NULL);
ASSERT(txg != 0);
/* dbuf is within the locked range */
ASSERT3U(db->db.db_offset, >=, zgd->zgd_rl->r_off);
ASSERT3U(db->db.db_offset + db->db.db_size, <=,
zgd->zgd_rl->r_off + zgd->zgd_rl->r_len);
SET_BOOKMARK(&zb, ds->ds_object,
db->db.db_object, db->db_level, db->db_blkid);
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
dmu_write_policy(os, dn, db->db_level, WP_DMU_SYNC, &zp);
DB_DNODE_EXIT(db);
/*
* If we're frozen (running ziltest), we always need to generate a bp.
*/
if (txg > spa_freeze_txg(os->os_spa))
return (dmu_sync_late_arrival(pio, os, done, zgd, &zp, &zb));
/*
* Grabbing db_mtx now provides a barrier between dbuf_sync_leaf()
* and us. If we determine that this txg is not yet syncing,
* but it begins to sync a moment later, that's OK because the
* sync thread will block in dbuf_sync_leaf() until we drop db_mtx.
*/
mutex_enter(&db->db_mtx);
if (txg <= spa_last_synced_txg(os->os_spa)) {
/*
* This txg has already synced. There's nothing to do.
*/
mutex_exit(&db->db_mtx);
return (SET_ERROR(EEXIST));
}
if (txg <= spa_syncing_txg(os->os_spa)) {
/*
* This txg is currently syncing, so we can't mess with
* the dirty record anymore; just write a new log block.
*/
mutex_exit(&db->db_mtx);
return (dmu_sync_late_arrival(pio, os, done, zgd, &zp, &zb));
}
dr = db->db_last_dirty;
while (dr && dr->dr_txg != txg)
dr = dr->dr_next;
if (dr == NULL) {
/*
* There's no dr for this dbuf, so it must have been freed.
* There's no need to log writes to freed blocks, so we're done.
*/
mutex_exit(&db->db_mtx);
return (SET_ERROR(ENOENT));
}
ASSERT(dr->dr_next == NULL || dr->dr_next->dr_txg < txg);
if (db->db_blkptr != NULL) {
/*
* We need to fill in zgd_bp with the current blkptr so that
* the nopwrite code can check if we're writing the same
* data that's already on disk. We can only nopwrite if we
* are sure that after making the copy, db_blkptr will not
* change until our i/o completes. We ensure this by
* holding the db_mtx, and only allowing nopwrite if the
* block is not already dirty (see below). This is verified
* by dmu_sync_done(), which VERIFYs that the db_blkptr has
* not changed.
*/
*zgd->zgd_bp = *db->db_blkptr;
}
/*
* Assume the on-disk data is X, the current syncing data (in
* txg - 1) is Y, and the current in-memory data is Z (currently
* in dmu_sync).
*
* We usually want to perform a nopwrite if X and Z are the
* same. However, if Y is different (i.e. the BP is going to
* change before this write takes effect), then a nopwrite will
* be incorrect - we would override with X, which could have
* been freed when Y was written.
*
* (Note that this is not a concern when we are nop-writing from
* syncing context, because X and Y must be identical, because
* all previous txgs have been synced.)
*
* Therefore, we disable nopwrite if the current BP could change
* before this TXG. There are two ways it could change: by
* being dirty (dr_next is non-NULL), or by being freed
* (dnode_block_freed()). This behavior is verified by
* zio_done(), which VERIFYs that the override BP is identical
* to the on-disk BP.
*/
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
if (dr->dr_next != NULL || dnode_block_freed(dn, db->db_blkid))
zp.zp_nopwrite = B_FALSE;
DB_DNODE_EXIT(db);
ASSERT(dr->dr_txg == txg);
if (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC ||
dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
/*
* We have already issued a sync write for this buffer,
* or this buffer has already been synced. It could not
* have been dirtied since, or we would have cleared the state.
*/
mutex_exit(&db->db_mtx);
return (SET_ERROR(EALREADY));
}
ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
dr->dt.dl.dr_override_state = DR_IN_DMU_SYNC;
mutex_exit(&db->db_mtx);
dsa = kmem_alloc(sizeof (dmu_sync_arg_t), KM_SLEEP);
dsa->dsa_dr = dr;
dsa->dsa_done = done;
dsa->dsa_zgd = zgd;
dsa->dsa_tx = NULL;
zio_nowait(arc_write(pio, os->os_spa, txg,
zgd->zgd_bp, dr->dt.dl.dr_data, DBUF_IS_L2CACHEABLE(db),
&zp, dmu_sync_ready, NULL, NULL, dmu_sync_done, dsa,
ZIO_PRIORITY_SYNC_WRITE, ZIO_FLAG_CANFAIL, &zb));
return (0);
}
int
dmu_object_set_nlevels(objset_t *os, uint64_t object, int nlevels, dmu_tx_t *tx)
{
dnode_t *dn;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
err = dnode_set_nlevels(dn, nlevels, tx);
dnode_rele(dn, FTAG);
return (err);
}
int
dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size, int ibs,
dmu_tx_t *tx)
{
dnode_t *dn;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
err = dnode_set_blksz(dn, size, ibs, tx);
dnode_rele(dn, FTAG);
return (err);
}
void
dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
dmu_tx_t *tx)
{
dnode_t *dn;
/*
* Send streams include each object's checksum function. This
* check ensures that the receiving system can understand the
* checksum function transmitted.
*/
ASSERT3U(checksum, <, ZIO_CHECKSUM_LEGACY_FUNCTIONS);
VERIFY0(dnode_hold(os, object, FTAG, &dn));
ASSERT3U(checksum, <, ZIO_CHECKSUM_FUNCTIONS);
dn->dn_checksum = checksum;
dnode_setdirty(dn, tx);
dnode_rele(dn, FTAG);
}
void
dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
dmu_tx_t *tx)
{
dnode_t *dn;
/*
* Send streams include each object's compression function. This
* check ensures that the receiving system can understand the
* compression function transmitted.
*/
ASSERT3U(compress, <, ZIO_COMPRESS_LEGACY_FUNCTIONS);
VERIFY0(dnode_hold(os, object, FTAG, &dn));
dn->dn_compress = compress;
dnode_setdirty(dn, tx);
dnode_rele(dn, FTAG);
}
/*
* Dirty an object and set the dirty record's raw flag. This is used
* when writing raw data to an object that will not effect the
* encryption parameters, specifically during raw receives.
*/
int
dmu_object_dirty_raw(objset_t *os, uint64_t object, dmu_tx_t *tx)
{
dnode_t *dn;
int err;
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
dmu_buf_will_change_crypt_params((dmu_buf_t *)dn->dn_dbuf, tx);
dnode_rele(dn, FTAG);
return (err);
}
int zfs_mdcomp_disable = 0;
/*
* When the "redundant_metadata" property is set to "most", only indirect
* blocks of this level and higher will have an additional ditto block.
*/
int zfs_redundant_metadata_most_ditto_level = 2;
void
dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
{
dmu_object_type_t type = dn ? dn->dn_type : DMU_OT_OBJSET;
boolean_t ismd = (level > 0 || DMU_OT_IS_METADATA(type) ||
(wp & WP_SPILL));
enum zio_checksum checksum = os->os_checksum;
enum zio_compress compress = os->os_compress;
enum zio_checksum dedup_checksum = os->os_dedup_checksum;
boolean_t dedup = B_FALSE;
boolean_t nopwrite = B_FALSE;
boolean_t dedup_verify = os->os_dedup_verify;
boolean_t encrypt = B_FALSE;
int copies = os->os_copies;
/*
* We maintain different write policies for each of the following
* types of data:
* 1. metadata
* 2. preallocated blocks (i.e. level-0 blocks of a dump device)
* 3. all other level 0 blocks
*/
if (ismd) {
if (zfs_mdcomp_disable) {
compress = ZIO_COMPRESS_EMPTY;
} else {
/*
* XXX -- we should design a compression algorithm
* that specializes in arrays of bps.
*/
compress = zio_compress_select(os->os_spa,
ZIO_COMPRESS_ON, ZIO_COMPRESS_ON);
}
/*
* Metadata always gets checksummed. If the data
* checksum is multi-bit correctable, and it's not a
* ZBT-style checksum, then it's suitable for metadata
* as well. Otherwise, the metadata checksum defaults
* to fletcher4.
*/
if (!(zio_checksum_table[checksum].ci_flags &
ZCHECKSUM_FLAG_METADATA) ||
(zio_checksum_table[checksum].ci_flags &
ZCHECKSUM_FLAG_EMBEDDED))
checksum = ZIO_CHECKSUM_FLETCHER_4;
if (os->os_redundant_metadata == ZFS_REDUNDANT_METADATA_ALL ||
(os->os_redundant_metadata ==
ZFS_REDUNDANT_METADATA_MOST &&
(level >= zfs_redundant_metadata_most_ditto_level ||
DMU_OT_IS_METADATA(type) || (wp & WP_SPILL))))
copies++;
} else if (wp & WP_NOFILL) {
ASSERT(level == 0);
/*
* If we're writing preallocated blocks, we aren't actually
* writing them so don't set any policy properties. These
* blocks are currently only used by an external subsystem
* outside of zfs (i.e. dump) and not written by the zio
* pipeline.
*/
compress = ZIO_COMPRESS_OFF;
checksum = ZIO_CHECKSUM_OFF;
} else {
compress = zio_compress_select(os->os_spa, dn->dn_compress,
compress);
checksum = (dedup_checksum == ZIO_CHECKSUM_OFF) ?
zio_checksum_select(dn->dn_checksum, checksum) :
dedup_checksum;
/*
* Determine dedup setting. If we are in dmu_sync(),
* we won't actually dedup now because that's all
* done in syncing context; but we do want to use the
* dedup checkum. If the checksum is not strong
* enough to ensure unique signatures, force
* dedup_verify.
*/
if (dedup_checksum != ZIO_CHECKSUM_OFF) {
dedup = (wp & WP_DMU_SYNC) ? B_FALSE : B_TRUE;
if (!(zio_checksum_table[checksum].ci_flags &
ZCHECKSUM_FLAG_DEDUP))
dedup_verify = B_TRUE;
}
/*
* Enable nopwrite if we have secure enough checksum
* algorithm (see comment in zio_nop_write) and
* compression is enabled. We don't enable nopwrite if
* dedup is enabled as the two features are mutually
* exclusive.
*/
nopwrite = (!dedup && (zio_checksum_table[checksum].ci_flags &
ZCHECKSUM_FLAG_NOPWRITE) &&
compress != ZIO_COMPRESS_OFF && zfs_nopwrite_enabled);
}
/*
* All objects in an encrypted objset are protected from modification
* via a MAC. Encrypted objects store their IV and salt in the last DVA
* in the bp, so we cannot use all copies. Encrypted objects are also
* not subject to nopwrite since writing the same data will still
* result in a new ciphertext. Only encrypted blocks can be dedup'd
* to avoid ambiguity in the dedup code since the DDT does not store
* object types.
*/
if (os->os_encrypted && (wp & WP_NOFILL) == 0) {
encrypt = B_TRUE;
if (DMU_OT_IS_ENCRYPTED(type)) {
copies = MIN(copies, SPA_DVAS_PER_BP - 1);
nopwrite = B_FALSE;
} else {
dedup = B_FALSE;
}
if (type == DMU_OT_DNODE || type == DMU_OT_OBJSET)
compress = ZIO_COMPRESS_EMPTY;
}
zp->zp_compress = compress;
zp->zp_checksum = checksum;
zp->zp_type = (wp & WP_SPILL) ? dn->dn_bonustype : type;
zp->zp_level = level;
zp->zp_copies = MIN(copies, spa_max_replication(os->os_spa));
zp->zp_dedup = dedup;
zp->zp_dedup_verify = dedup && dedup_verify;
zp->zp_nopwrite = nopwrite;
zp->zp_encrypt = encrypt;
zp->zp_byteorder = ZFS_HOST_BYTEORDER;
bzero(zp->zp_salt, ZIO_DATA_SALT_LEN);
bzero(zp->zp_iv, ZIO_DATA_IV_LEN);
bzero(zp->zp_mac, ZIO_DATA_MAC_LEN);
ASSERT3U(zp->zp_compress, !=, ZIO_COMPRESS_INHERIT);
}
/*
* This function is only called from zfs_holey_common() for zpl_llseek()
* in order to determine the location of holes. In order to accurately
* report holes all dirty data must be synced to disk. This causes extremely
* poor performance when seeking for holes in a dirty file. As a compromise,
* only provide hole data when the dnode is clean. When a dnode is dirty
* report the dnode as having no holes which is always a safe thing to do.
*/
int
dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole, uint64_t *off)
{
dnode_t *dn;
int i, err;
boolean_t clean = B_TRUE;
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
/*
* Check if dnode is dirty
*/
for (i = 0; i < TXG_SIZE; i++) {
if (list_link_active(&dn->dn_dirty_link[i])) {
clean = B_FALSE;
break;
}
}
/*
* If compatibility option is on, sync any current changes before
* we go trundling through the block pointers.
*/
if (!clean && zfs_dmu_offset_next_sync) {
clean = B_TRUE;
dnode_rele(dn, FTAG);
txg_wait_synced(dmu_objset_pool(os), 0);
err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
}
if (clean)
err = dnode_next_offset(dn,
(hole ? DNODE_FIND_HOLE : 0), off, 1, 1, 0);
else
err = SET_ERROR(EBUSY);
dnode_rele(dn, FTAG);
return (err);
}
void
__dmu_object_info_from_dnode(dnode_t *dn, dmu_object_info_t *doi)
{
dnode_phys_t *dnp = dn->dn_phys;
doi->doi_data_block_size = dn->dn_datablksz;
doi->doi_metadata_block_size = dn->dn_indblkshift ?
1ULL << dn->dn_indblkshift : 0;
doi->doi_type = dn->dn_type;
doi->doi_bonus_type = dn->dn_bonustype;
doi->doi_bonus_size = dn->dn_bonuslen;
doi->doi_dnodesize = dn->dn_num_slots << DNODE_SHIFT;
doi->doi_indirection = dn->dn_nlevels;
doi->doi_checksum = dn->dn_checksum;
doi->doi_compress = dn->dn_compress;
doi->doi_nblkptr = dn->dn_nblkptr;
doi->doi_physical_blocks_512 = (DN_USED_BYTES(dnp) + 256) >> 9;
doi->doi_max_offset = (dn->dn_maxblkid + 1) * dn->dn_datablksz;
doi->doi_fill_count = 0;
for (int i = 0; i < dnp->dn_nblkptr; i++)
doi->doi_fill_count += BP_GET_FILL(&dnp->dn_blkptr[i]);
}
void
dmu_object_info_from_dnode(dnode_t *dn, dmu_object_info_t *doi)
{
rw_enter(&dn->dn_struct_rwlock, RW_READER);
mutex_enter(&dn->dn_mtx);
__dmu_object_info_from_dnode(dn, doi);
mutex_exit(&dn->dn_mtx);
rw_exit(&dn->dn_struct_rwlock);
}
/*
* Get information on a DMU object.
* If doi is NULL, just indicates whether the object exists.
*/
int
dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi)
{
dnode_t *dn;
int err = dnode_hold(os, object, FTAG, &dn);
if (err)
return (err);
if (doi != NULL)
dmu_object_info_from_dnode(dn, doi);
dnode_rele(dn, FTAG);
return (0);
}
/*
* As above, but faster; can be used when you have a held dbuf in hand.
*/
void
dmu_object_info_from_db(dmu_buf_t *db_fake, dmu_object_info_t *doi)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
DB_DNODE_ENTER(db);
dmu_object_info_from_dnode(DB_DNODE(db), doi);
DB_DNODE_EXIT(db);
}
/*
* Faster still when you only care about the size.
* This is specifically optimized for zfs_getattr().
*/
void
dmu_object_size_from_db(dmu_buf_t *db_fake, uint32_t *blksize,
u_longlong_t *nblk512)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
dnode_t *dn;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
*blksize = dn->dn_datablksz;
/* add in number of slots used for the dnode itself */
*nblk512 = ((DN_USED_BYTES(dn->dn_phys) + SPA_MINBLOCKSIZE/2) >>
SPA_MINBLOCKSHIFT) + dn->dn_num_slots;
DB_DNODE_EXIT(db);
}
void
dmu_object_dnsize_from_db(dmu_buf_t *db_fake, int *dnsize)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
dnode_t *dn;
DB_DNODE_ENTER(db);
dn = DB_DNODE(db);
*dnsize = dn->dn_num_slots << DNODE_SHIFT;
DB_DNODE_EXIT(db);
}
void
byteswap_uint64_array(void *vbuf, size_t size)
{
uint64_t *buf = vbuf;
size_t count = size >> 3;
int i;
ASSERT((size & 7) == 0);
for (i = 0; i < count; i++)
buf[i] = BSWAP_64(buf[i]);
}
void
byteswap_uint32_array(void *vbuf, size_t size)
{
uint32_t *buf = vbuf;
size_t count = size >> 2;
int i;
ASSERT((size & 3) == 0);
for (i = 0; i < count; i++)
buf[i] = BSWAP_32(buf[i]);
}
void
byteswap_uint16_array(void *vbuf, size_t size)
{
uint16_t *buf = vbuf;
size_t count = size >> 1;
int i;
ASSERT((size & 1) == 0);
for (i = 0; i < count; i++)
buf[i] = BSWAP_16(buf[i]);
}
/* ARGSUSED */
void
byteswap_uint8_array(void *vbuf, size_t size)
{
}
void
dmu_init(void)
{
abd_init();
zfs_dbgmsg_init();
sa_cache_init();
xuio_stat_init();
dmu_objset_init();
dnode_init();
zfetch_init();
dmu_tx_init();
l2arc_init();
arc_init();
dbuf_init();
}
void
dmu_fini(void)
{
arc_fini(); /* arc depends on l2arc, so arc must go first */
l2arc_fini();
dmu_tx_fini();
zfetch_fini();
dbuf_fini();
dnode_fini();
dmu_objset_fini();
xuio_stat_fini();
sa_cache_fini();
zfs_dbgmsg_fini();
abd_fini();
}
#if defined(_KERNEL) && defined(HAVE_SPL)
EXPORT_SYMBOL(dmu_bonus_hold);
EXPORT_SYMBOL(dmu_buf_hold_array_by_bonus);
EXPORT_SYMBOL(dmu_buf_rele_array);
EXPORT_SYMBOL(dmu_prefetch);
EXPORT_SYMBOL(dmu_free_range);
EXPORT_SYMBOL(dmu_free_long_range);
EXPORT_SYMBOL(dmu_free_long_range_raw);
EXPORT_SYMBOL(dmu_free_long_object);
EXPORT_SYMBOL(dmu_free_long_object_raw);
EXPORT_SYMBOL(dmu_read);
EXPORT_SYMBOL(dmu_read_by_dnode);
EXPORT_SYMBOL(dmu_write);
EXPORT_SYMBOL(dmu_write_by_dnode);
EXPORT_SYMBOL(dmu_prealloc);
EXPORT_SYMBOL(dmu_object_info);
EXPORT_SYMBOL(dmu_object_info_from_dnode);
EXPORT_SYMBOL(dmu_object_info_from_db);
EXPORT_SYMBOL(dmu_object_size_from_db);
EXPORT_SYMBOL(dmu_object_dnsize_from_db);
EXPORT_SYMBOL(dmu_object_set_nlevels);
EXPORT_SYMBOL(dmu_object_set_blocksize);
EXPORT_SYMBOL(dmu_object_set_checksum);
EXPORT_SYMBOL(dmu_object_set_compress);
EXPORT_SYMBOL(dmu_write_policy);
EXPORT_SYMBOL(dmu_sync);
EXPORT_SYMBOL(dmu_request_arcbuf);
EXPORT_SYMBOL(dmu_return_arcbuf);
EXPORT_SYMBOL(dmu_assign_arcbuf_by_dnode);
EXPORT_SYMBOL(dmu_assign_arcbuf_by_dbuf);
EXPORT_SYMBOL(dmu_buf_hold);
EXPORT_SYMBOL(dmu_ot);
/* BEGIN CSTYLED */
module_param(zfs_mdcomp_disable, int, 0644);
MODULE_PARM_DESC(zfs_mdcomp_disable, "Disable meta data compression");
module_param(zfs_nopwrite_enabled, int, 0644);
MODULE_PARM_DESC(zfs_nopwrite_enabled, "Enable NOP writes");
module_param(zfs_per_txg_dirty_frees_percent, ulong, 0644);
MODULE_PARM_DESC(zfs_per_txg_dirty_frees_percent,
"percentage of dirtied blocks from frees in one TXG");
module_param(zfs_dmu_offset_next_sync, int, 0644);
MODULE_PARM_DESC(zfs_dmu_offset_next_sync,
"Enable forcing txg sync to find holes");
/* END CSTYLED */
#endif
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