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mirror_zfs/include/sys/zio_impl.h
Michael Niewöhner 10b3c7f5e4 Add zstd support to zfs 
This PR adds two new compression types, based on ZStandard:

- zstd: A basic ZStandard compression algorithm Available compression.
  Levels for zstd are zstd-1 through zstd-19, where the compression
  increases with every level, but speed decreases.

- zstd-fast: A faster version of the ZStandard compression algorithm
  zstd-fast is basically a "negative" level of zstd. The compression
  decreases with every level, but speed increases.

  Available compression levels for zstd-fast:
   - zstd-fast-1 through zstd-fast-10
   - zstd-fast-20 through zstd-fast-100 (in increments of 10)
   - zstd-fast-500 and zstd-fast-1000

For more information check the man page.

Implementation details:

Rather than treat each level of zstd as a different algorithm (as was
done historically with gzip), the block pointer `enum zio_compress`
value is simply zstd for all levels, including zstd-fast, since they all
use the same decompression function.

The compress= property (a 64bit unsigned integer) uses the lower 7 bits
to store the compression algorithm (matching the number of bits used in
a block pointer, as the 8th bit was borrowed for embedded block
pointers).  The upper bits are used to store the compression level.

It is necessary to be able to determine what compression level was used
when later reading a block back, so the concept used in LZ4, where the
first 32bits of the on-disk value are the size of the compressed data
(since the allocation is rounded up to the nearest ashift), was
extended, and we store the version of ZSTD and the level as well as the
compressed size. This value is returned when decompressing a block, so
that if the block needs to be recompressed (L2ARC, nop-write, etc), that
the same parameters will be used to result in the matching checksum.

All of the internal ZFS code ( `arc_buf_hdr_t`, `objset_t`,
`zio_prop_t`, etc.) uses the separated _compress and _complevel
variables.  Only the properties ZAP contains the combined/bit-shifted
value. The combined value is split when the compression_changed_cb()
callback is called, and sets both objset members (os_compress and
os_complevel).

The userspace tools all use the combined/bit-shifted value.

Additional notes:

zdb can now also decode the ZSTD compression header (flag -Z) and
inspect the size, version and compression level saved in that header.
For each record, if it is ZSTD compressed, the parameters of the decoded
compression header get printed.

ZSTD is included with all current tests and new tests are added
as-needed.

Per-dataset feature flags now get activated when the property is set.
If a compression algorithm requires a feature flag, zfs activates the
feature when the property is set, rather than waiting for the first
block to be born.  This is currently only used by zstd but can be
extended as needed.

Portions-Sponsored-By: The FreeBSD Foundation
Co-authored-by: Allan Jude <allanjude@freebsd.org>
Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Co-authored-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Co-authored-by: Michael Niewöhner <foss@mniewoehner.de>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Signed-off-by: Allan Jude <allanjude@freebsd.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Closes #6247
Closes #9024
Closes #10277
Closes #10278
2020-08-20 10:30:06 -07:00

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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 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 2012, 2015 by Delphix. All rights reserved.
*/
#ifndef _ZIO_IMPL_H
#define _ZIO_IMPL_H
#ifdef __cplusplus
extern "C" {
#endif
/*
* XXX -- Describe ZFS I/O pipeline here. Fill in as needed.
*
* The ZFS I/O pipeline is comprised of various stages which are defined
* in the zio_stage enum below. The individual stages are used to construct
* these basic I/O operations: Read, Write, Free, Claim, and Ioctl.
*
* I/O operations: (XXX - provide detail for each of the operations)
*
* Read:
* Write:
* Free:
* Claim:
* Ioctl:
*
* Although the most common pipeline are used by the basic I/O operations
* above, there are some helper pipelines (one could consider them
* sub-pipelines) which are used internally by the ZIO module and are
* explained below:
*
* Interlock Pipeline:
* The interlock pipeline is the most basic pipeline and is used by all
* of the I/O operations. The interlock pipeline does not perform any I/O
* and is used to coordinate the dependencies between I/Os that are being
* issued (i.e. the parent/child relationship).
*
* Vdev child Pipeline:
* The vdev child pipeline is responsible for performing the physical I/O.
* It is in this pipeline where the I/O are queued and possibly cached.
*
* In addition to performing I/O, the pipeline is also responsible for
* data transformations. The transformations performed are based on the
* specific properties that user may have selected and modify the
* behavior of the pipeline. Examples of supported transformations are
* compression, dedup, and nop writes. Transformations will either modify
* the data or the pipeline. This list below further describes each of
* the supported transformations:
*
* Compression:
* ZFS supports five different flavors of compression -- gzip, lzjb, lz4, zle,
* and zstd. Compression occurs as part of the write pipeline and is
* performed in the ZIO_STAGE_WRITE_BP_INIT stage.
*
* Dedup:
* Dedup reads are handled by the ZIO_STAGE_DDT_READ_START and
* ZIO_STAGE_DDT_READ_DONE stages. These stages are added to an existing
* read pipeline if the dedup bit is set on the block pointer.
* Writing a dedup block is performed by the ZIO_STAGE_DDT_WRITE stage
* and added to a write pipeline if a user has enabled dedup on that
* particular dataset.
*
* NOP Write:
* The NOP write feature is performed by the ZIO_STAGE_NOP_WRITE stage
* and is added to an existing write pipeline if a cryptographically
* secure checksum (i.e. SHA256) is enabled and compression is turned on.
* The NOP write stage will compare the checksums of the current data
* on-disk (level-0 blocks only) and the data that is currently being written.
* If the checksum values are identical then the pipeline is converted to
* an interlock pipeline skipping block allocation and bypassing the
* physical I/O. The nop write feature can handle writes in either
* syncing or open context (i.e. zil writes) and as a result is mutually
* exclusive with dedup.
*
* Encryption:
* Encryption and authentication is handled by the ZIO_STAGE_ENCRYPT stage.
* This stage determines how the encryption metadata is stored in the bp.
* Decryption and MAC verification is performed during zio_decrypt() as a
* transform callback. Encryption is mutually exclusive with nopwrite, because
* blocks with the same plaintext will be encrypted with different salts and
* IV's (if dedup is off), and therefore have different ciphertexts. For dedup
* blocks we deterministically generate the IV and salt by performing an HMAC
* of the plaintext, which is computationally expensive, but allows us to keep
* support for encrypted dedup. See the block comment in zio_crypt.c for
* details.
*/
/*
* zio pipeline stage definitions
*/
enum zio_stage {
ZIO_STAGE_OPEN = 1 << 0, /* RWFCI */
ZIO_STAGE_READ_BP_INIT = 1 << 1, /* R---- */
ZIO_STAGE_WRITE_BP_INIT = 1 << 2, /* -W--- */
ZIO_STAGE_FREE_BP_INIT = 1 << 3, /* --F-- */
ZIO_STAGE_ISSUE_ASYNC = 1 << 4, /* RWF-- */
ZIO_STAGE_WRITE_COMPRESS = 1 << 5, /* -W--- */
ZIO_STAGE_ENCRYPT = 1 << 6, /* -W--- */
ZIO_STAGE_CHECKSUM_GENERATE = 1 << 7, /* -W--- */
ZIO_STAGE_NOP_WRITE = 1 << 8, /* -W--- */
ZIO_STAGE_DDT_READ_START = 1 << 9, /* R---- */
ZIO_STAGE_DDT_READ_DONE = 1 << 10, /* R---- */
ZIO_STAGE_DDT_WRITE = 1 << 11, /* -W--- */
ZIO_STAGE_DDT_FREE = 1 << 12, /* --F-- */
ZIO_STAGE_GANG_ASSEMBLE = 1 << 13, /* RWFC- */
ZIO_STAGE_GANG_ISSUE = 1 << 14, /* RWFC- */
ZIO_STAGE_DVA_THROTTLE = 1 << 15, /* -W--- */
ZIO_STAGE_DVA_ALLOCATE = 1 << 16, /* -W--- */
ZIO_STAGE_DVA_FREE = 1 << 17, /* --F-- */
ZIO_STAGE_DVA_CLAIM = 1 << 18, /* ---C- */
ZIO_STAGE_READY = 1 << 19, /* RWFCI */
ZIO_STAGE_VDEV_IO_START = 1 << 20, /* RW--I */
ZIO_STAGE_VDEV_IO_DONE = 1 << 21, /* RW--I */
ZIO_STAGE_VDEV_IO_ASSESS = 1 << 22, /* RW--I */
ZIO_STAGE_CHECKSUM_VERIFY = 1 << 23, /* R---- */
ZIO_STAGE_DONE = 1 << 24 /* RWFCI */
};
#define ZIO_INTERLOCK_STAGES \
(ZIO_STAGE_READY | \
ZIO_STAGE_DONE)
#define ZIO_INTERLOCK_PIPELINE \
ZIO_INTERLOCK_STAGES
#define ZIO_VDEV_IO_STAGES \
(ZIO_STAGE_VDEV_IO_START | \
ZIO_STAGE_VDEV_IO_DONE | \
ZIO_STAGE_VDEV_IO_ASSESS)
#define ZIO_VDEV_CHILD_PIPELINE \
(ZIO_VDEV_IO_STAGES | \
ZIO_STAGE_DONE)
#define ZIO_READ_COMMON_STAGES \
(ZIO_INTERLOCK_STAGES | \
ZIO_VDEV_IO_STAGES | \
ZIO_STAGE_CHECKSUM_VERIFY)
#define ZIO_READ_PHYS_PIPELINE \
ZIO_READ_COMMON_STAGES
#define ZIO_READ_PIPELINE \
(ZIO_READ_COMMON_STAGES | \
ZIO_STAGE_READ_BP_INIT)
#define ZIO_DDT_CHILD_READ_PIPELINE \
ZIO_READ_COMMON_STAGES
#define ZIO_DDT_READ_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_READ_BP_INIT | \
ZIO_STAGE_DDT_READ_START | \
ZIO_STAGE_DDT_READ_DONE)
#define ZIO_WRITE_COMMON_STAGES \
(ZIO_INTERLOCK_STAGES | \
ZIO_VDEV_IO_STAGES | \
ZIO_STAGE_ISSUE_ASYNC | \
ZIO_STAGE_CHECKSUM_GENERATE)
#define ZIO_WRITE_PHYS_PIPELINE \
ZIO_WRITE_COMMON_STAGES
#define ZIO_REWRITE_PIPELINE \
(ZIO_WRITE_COMMON_STAGES | \
ZIO_STAGE_WRITE_COMPRESS | \
ZIO_STAGE_ENCRYPT | \
ZIO_STAGE_WRITE_BP_INIT)
#define ZIO_WRITE_PIPELINE \
(ZIO_WRITE_COMMON_STAGES | \
ZIO_STAGE_WRITE_BP_INIT | \
ZIO_STAGE_WRITE_COMPRESS | \
ZIO_STAGE_ENCRYPT | \
ZIO_STAGE_DVA_THROTTLE | \
ZIO_STAGE_DVA_ALLOCATE)
#define ZIO_DDT_CHILD_WRITE_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_VDEV_IO_STAGES | \
ZIO_STAGE_DVA_THROTTLE | \
ZIO_STAGE_DVA_ALLOCATE)
#define ZIO_DDT_WRITE_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_WRITE_BP_INIT | \
ZIO_STAGE_ISSUE_ASYNC | \
ZIO_STAGE_WRITE_COMPRESS | \
ZIO_STAGE_ENCRYPT | \
ZIO_STAGE_CHECKSUM_GENERATE | \
ZIO_STAGE_DDT_WRITE)
#define ZIO_GANG_STAGES \
(ZIO_STAGE_GANG_ASSEMBLE | \
ZIO_STAGE_GANG_ISSUE)
#define ZIO_FREE_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_FREE_BP_INIT | \
ZIO_STAGE_DVA_FREE)
#define ZIO_DDT_FREE_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_FREE_BP_INIT | \
ZIO_STAGE_ISSUE_ASYNC | \
ZIO_STAGE_DDT_FREE)
#define ZIO_CLAIM_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_DVA_CLAIM)
#define ZIO_IOCTL_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_VDEV_IO_START | \
ZIO_STAGE_VDEV_IO_ASSESS)
#define ZIO_TRIM_PIPELINE \
(ZIO_INTERLOCK_STAGES | \
ZIO_STAGE_ISSUE_ASYNC | \
ZIO_VDEV_IO_STAGES)
#define ZIO_BLOCKING_STAGES \
(ZIO_STAGE_DVA_ALLOCATE | \
ZIO_STAGE_DVA_CLAIM | \
ZIO_STAGE_VDEV_IO_START)
extern void zio_inject_init(void);
extern void zio_inject_fini(void);
#ifdef __cplusplus
}
#endif
#endif /* _ZIO_IMPL_H */
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