zfs/include/sys/zio_impl.h - backupdr - Git at Google

 /*
  * 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 three different flavors of compression -- gzip, lzjb, and
  * zle. 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 */
	/*
	* 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 three different flavors of compression -- gzip, lzjb, and
	* zle. 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 */