zfs/include/sys/dmu_objset.h

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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) 2013 by Saso Kiselkov. All rights reserved.
* Copyright (c) 2012, 2014 by Delphix. All rights reserved.
* Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
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*/
/* Portions Copyright 2010 Robert Milkowski */
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#ifndef _SYS_DMU_OBJSET_H
#define _SYS_DMU_OBJSET_H
#include <sys/spa.h>
#include <sys/arc.h>
#include <sys/txg.h>
#include <sys/zfs_context.h>
#include <sys/dnode.h>
#include <sys/zio.h>
#include <sys/zil.h>
#include <sys/sa.h>
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#ifdef __cplusplus
extern "C" {
#endif
extern krwlock_t os_lock;
struct dsl_pool;
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struct dsl_dataset;
struct dmu_tx;
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#define OBJSET_PHYS_SIZE 2048
#define OBJSET_OLD_PHYS_SIZE 1024
#define OBJSET_BUF_HAS_USERUSED(buf) \
(arc_buf_size(buf) > OBJSET_OLD_PHYS_SIZE)
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#define OBJSET_FLAG_USERACCOUNTING_COMPLETE (1ULL<<0)
#define OBJSET_FLAG_USEROBJACCOUNTING_COMPLETE (1ULL<<1)
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typedef struct objset_phys {
dnode_phys_t os_meta_dnode;
zil_header_t os_zil_header;
uint64_t os_type;
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uint64_t os_flags;
char os_pad[OBJSET_PHYS_SIZE - sizeof (dnode_phys_t)*3 -
sizeof (zil_header_t) - sizeof (uint64_t)*2];
dnode_phys_t os_userused_dnode;
dnode_phys_t os_groupused_dnode;
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} objset_phys_t;
typedef int (*dmu_objset_upgrade_cb_t)(objset_t *);
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struct objset {
/* Immutable: */
struct dsl_dataset *os_dsl_dataset;
spa_t *os_spa;
arc_buf_t *os_phys_buf;
objset_phys_t *os_phys;
/*
* The following "special" dnodes have no parent, are exempt
* from dnode_move(), and are not recorded in os_dnodes, but they
* root their descendents in this objset using handles anyway, so
* that all access to dnodes from dbufs consistently uses handles.
*/
dnode_handle_t os_meta_dnode;
dnode_handle_t os_userused_dnode;
dnode_handle_t os_groupused_dnode;
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zilog_t *os_zil;
list_node_t os_evicting_node;
/* can change, under dsl_dir's locks: */
Implement large_dnode pool feature Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3542
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uint64_t os_dnodesize; /* default dnode size for new objects */
enum zio_checksum os_checksum;
enum zio_compress os_compress;
uint8_t os_copies;
enum zio_checksum os_dedup_checksum;
boolean_t os_dedup_verify;
zfs_logbias_op_t os_logbias;
zfs_cache_type_t os_primary_cache;
zfs_cache_type_t os_secondary_cache;
zfs_sync_type_t os_sync;
zfs_redundant_metadata_type_t os_redundant_metadata;
Illumos 5027 - zfs large block support 5027 zfs large block support Reviewed by: Alek Pinchuk <pinchuk.alek@gmail.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Josef 'Jeff' Sipek <josef.sipek@nexenta.com> Reviewed by: Richard Elling <richard.elling@richardelling.com> Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@omniti.com> References: https://www.illumos.org/issues/5027 https://github.com/illumos/illumos-gate/commit/b515258 Porting Notes: * Included in this patch is a tiny ISP2() cleanup in zio_init() from Illumos 5255. * Unlike the upstream Illumos commit this patch does not impose an arbitrary 128K block size limit on volumes. Volumes, like filesystems, are limited by the zfs_max_recordsize=1M module option. * By default the maximum record size is limited to 1M by the module option zfs_max_recordsize. This value may be safely increased up to 16M which is the largest block size supported by the on-disk format. At the moment, 1M blocks clearly offer a significant performance improvement but the benefits of going beyond this for the majority of workloads are less clear. * The illumos version of this patch increased DMU_MAX_ACCESS to 32M. This was determined not to be large enough when using 16M blocks because the zfs_make_xattrdir() function will fail (EFBIG) when assigning a TX. This was immediately observed under Linux because all newly created files must have a security xattr created and that was failing. Therefore, we've set DMU_MAX_ACCESS to 64M. * On 32-bit platforms a hard limit of 1M is set for blocks due to the limited virtual address space. We should be able to relax this one the ABD patches are merged. Ported-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #354
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int os_recordsize;
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/* no lock needed: */
struct dmu_tx *os_synctx; /* XXX sketchy */
blkptr_t *os_rootbp;
zil_header_t os_zil_header;
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list_t os_synced_dnodes;
uint64_t os_flags;
Backfill metadnode more intelligently Only attempt to backfill lower metadnode object numbers if at least 4096 objects have been freed since the last rescan, and at most once per transaction group. This avoids a pathology in dmu_object_alloc() that caused O(N^2) behavior for create-heavy workloads and substantially improves object creation rates. As summarized by @mahrens in #4636: "Normally, the object allocator simply checks to see if the next object is available. The slow calls happened when dmu_object_alloc() checks to see if it can backfill lower object numbers. This happens every time we move on to a new L1 indirect block (i.e. every 32 * 128 = 4096 objects). When re-checking lower object numbers, we use the on-disk fill count (blkptr_t:blk_fill) to quickly skip over indirect blocks that don’t have enough free dnodes (defined as an L2 with at least 393,216 of 524,288 dnodes free). Therefore, we may find that a block of dnodes has a low (or zero) fill count, and yet we can’t allocate any of its dnodes, because they've been allocated in memory but not yet written to disk. In this case we have to hold each of the dnodes and then notice that it has been allocated in memory. The end result is that allocating N objects in the same TXG can require CPU usage proportional to N^2." Add a tunable dmu_rescan_dnode_threshold to define the number of objects that must be freed before a rescan is performed. Don't bother to export this as a module option because testing doesn't show a compelling reason to change it. The vast majority of the performance gain comes from limit the rescan to at most once per TXG. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
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uint64_t os_freed_dnodes;
boolean_t os_rescan_dnodes;
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/* Protected by os_obj_lock */
kmutex_t os_obj_lock;
uint64_t os_obj_next;
/* Protected by os_lock */
kmutex_t os_lock;
list_t os_dirty_dnodes[TXG_SIZE];
list_t os_free_dnodes[TXG_SIZE];
list_t os_dnodes;
list_t os_downgraded_dbufs;
/* stuff we store for the user */
kmutex_t os_user_ptr_lock;
void *os_user_ptr;
sa_os_t *os_sa;
/* kernel thread to upgrade this dataset */
kmutex_t os_upgrade_lock;
taskqid_t os_upgrade_id;
dmu_objset_upgrade_cb_t os_upgrade_cb;
boolean_t os_upgrade_exit;
int os_upgrade_status;
};
#define DMU_META_OBJSET 0
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#define DMU_META_DNODE_OBJECT 0
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#define DMU_OBJECT_IS_SPECIAL(obj) ((int64_t)(obj) <= 0)
#define DMU_META_DNODE(os) ((os)->os_meta_dnode.dnh_dnode)
#define DMU_USERUSED_DNODE(os) ((os)->os_userused_dnode.dnh_dnode)
#define DMU_GROUPUSED_DNODE(os) ((os)->os_groupused_dnode.dnh_dnode)
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#define DMU_OS_IS_L2CACHEABLE(os) \
((os)->os_secondary_cache == ZFS_CACHE_ALL || \
(os)->os_secondary_cache == ZFS_CACHE_METADATA)
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/* called from zpl */
int dmu_objset_hold(const char *name, void *tag, objset_t **osp);
int dmu_objset_own(const char *name, dmu_objset_type_t type,
boolean_t readonly, void *tag, objset_t **osp);
int dmu_objset_own_obj(struct dsl_pool *dp, uint64_t obj,
dmu_objset_type_t type, boolean_t readonly, void *tag, objset_t **osp);
void dmu_objset_refresh_ownership(objset_t *os, void *tag);
void dmu_objset_rele(objset_t *os, void *tag);
void dmu_objset_disown(objset_t *os, void *tag);
int dmu_objset_from_ds(struct dsl_dataset *ds, objset_t **osp);
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void dmu_objset_stats(objset_t *os, nvlist_t *nv);
void dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat);
void dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
uint64_t *usedobjsp, uint64_t *availobjsp);
uint64_t dmu_objset_fsid_guid(objset_t *os);
int dmu_objset_find_dp(struct dsl_pool *dp, uint64_t ddobj,
int func(struct dsl_pool *, struct dsl_dataset *, void *),
void *arg, int flags);
void dmu_objset_evict_dbufs(objset_t *os);
timestruc_t dmu_objset_snap_cmtime(objset_t *os);
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/* called from dsl */
void dmu_objset_sync(objset_t *os, zio_t *zio, dmu_tx_t *tx);
boolean_t dmu_objset_is_dirty(objset_t *os, uint64_t txg);
objset_t *dmu_objset_create_impl(spa_t *spa, struct dsl_dataset *ds,
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blkptr_t *bp, dmu_objset_type_t type, dmu_tx_t *tx);
int dmu_objset_open_impl(spa_t *spa, struct dsl_dataset *ds, blkptr_t *bp,
objset_t **osp);
void dmu_objset_evict(objset_t *os);
void dmu_objset_do_userquota_updates(objset_t *os, dmu_tx_t *tx);
void dmu_objset_userquota_get_ids(dnode_t *dn, boolean_t before, dmu_tx_t *tx);
boolean_t dmu_objset_userused_enabled(objset_t *os);
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int dmu_objset_userspace_upgrade(objset_t *os);
boolean_t dmu_objset_userspace_present(objset_t *os);
boolean_t dmu_objset_userobjused_enabled(objset_t *os);
void dmu_objset_userobjspace_upgrade(objset_t *os);
boolean_t dmu_objset_userobjspace_present(objset_t *os);
static inline boolean_t dmu_objset_userobjspace_upgradable(objset_t *os)
{
return (dmu_objset_type(os) == DMU_OST_ZFS &&
dmu_objset_userobjused_enabled(os) &&
!dmu_objset_userobjspace_present(os));
}
int dmu_fsname(const char *snapname, char *buf);
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void dmu_objset_evict_done(objset_t *os);
void dmu_objset_init(void);
void dmu_objset_fini(void);
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#ifdef __cplusplus
}
#endif
#endif /* _SYS_DMU_OBJSET_H */