diff options
Diffstat (limited to 'sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio_impl.h')
| -rw-r--r-- | sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio_impl.h | 101 |
1 files changed, 86 insertions, 15 deletions
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio_impl.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio_impl.h index 86ea979..aa44744 100644 --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio_impl.h +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio_impl.h @@ -23,6 +23,10 @@ * Use is subject to license terms. */ +/* + * Copyright (c) 2012 by Delphix. All rights reserved. + */ + #ifndef _ZIO_IMPL_H #define _ZIO_IMPL_H @@ -34,6 +38,70 @@ extern "C" { #endif /* + * XXX -- Describe ZFS I/O pipleine 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 crypographically + * 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. + */ + +/* * zio pipeline stage definitions */ enum zio_stage { @@ -46,27 +114,29 @@ enum zio_stage { ZIO_STAGE_CHECKSUM_GENERATE = 1 << 5, /* -W--- */ - ZIO_STAGE_DDT_READ_START = 1 << 6, /* R---- */ - ZIO_STAGE_DDT_READ_DONE = 1 << 7, /* R---- */ - ZIO_STAGE_DDT_WRITE = 1 << 8, /* -W--- */ - ZIO_STAGE_DDT_FREE = 1 << 9, /* --F-- */ + ZIO_STAGE_NOP_WRITE = 1 << 6, /* -W--- */ - ZIO_STAGE_GANG_ASSEMBLE = 1 << 10, /* RWFC- */ - ZIO_STAGE_GANG_ISSUE = 1 << 11, /* RWFC- */ + ZIO_STAGE_DDT_READ_START = 1 << 7, /* R---- */ + ZIO_STAGE_DDT_READ_DONE = 1 << 8, /* R---- */ + ZIO_STAGE_DDT_WRITE = 1 << 9, /* -W--- */ + ZIO_STAGE_DDT_FREE = 1 << 10, /* --F-- */ - ZIO_STAGE_DVA_ALLOCATE = 1 << 12, /* -W--- */ - ZIO_STAGE_DVA_FREE = 1 << 13, /* --F-- */ - ZIO_STAGE_DVA_CLAIM = 1 << 14, /* ---C- */ + ZIO_STAGE_GANG_ASSEMBLE = 1 << 11, /* RWFC- */ + ZIO_STAGE_GANG_ISSUE = 1 << 12, /* RWFC- */ - ZIO_STAGE_READY = 1 << 15, /* RWFCI */ + ZIO_STAGE_DVA_ALLOCATE = 1 << 13, /* -W--- */ + ZIO_STAGE_DVA_FREE = 1 << 14, /* --F-- */ + ZIO_STAGE_DVA_CLAIM = 1 << 15, /* ---C- */ - ZIO_STAGE_VDEV_IO_START = 1 << 16, /* RWF-I */ - ZIO_STAGE_VDEV_IO_DONE = 1 << 17, /* RWF-- */ - ZIO_STAGE_VDEV_IO_ASSESS = 1 << 18, /* RWF-I */ + ZIO_STAGE_READY = 1 << 16, /* RWFCI */ - ZIO_STAGE_CHECKSUM_VERIFY = 1 << 19, /* R---- */ + ZIO_STAGE_VDEV_IO_START = 1 << 17, /* RWF-I */ + ZIO_STAGE_VDEV_IO_DONE = 1 << 18, /* RWF-- */ + ZIO_STAGE_VDEV_IO_ASSESS = 1 << 19, /* RWF-I */ - ZIO_STAGE_DONE = 1 << 20 /* RWFCI */ + ZIO_STAGE_CHECKSUM_VERIFY = 1 << 20, /* R---- */ + + ZIO_STAGE_DONE = 1 << 21 /* RWFCI */ }; #define ZIO_INTERLOCK_STAGES \ @@ -143,6 +213,7 @@ enum zio_stage { #define ZIO_FREE_PIPELINE \ (ZIO_INTERLOCK_STAGES | \ ZIO_STAGE_FREE_BP_INIT | \ + ZIO_STAGE_ISSUE_ASYNC | \ ZIO_STAGE_DVA_FREE | \ ZIO_STAGE_VDEV_IO_START | \ ZIO_STAGE_VDEV_IO_ASSESS) |
