zfs/sys/zio.h

	zio.h revision fa9e4066f08beec538e775443c5be79dd423fcab
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _ZIO_H
#define _ZIO_H

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/txg.h>
#include <sys/avl.h>
#include <sys/dkio.h>
#include <sys/fs/zfs.h>

#ifdef  __cplusplus
extern "C" {
#endif

#define ZBT_MAGIC   0x210da7ab10c7a11ULL    /* zio data bloc tail */

typedef struct zio_block_tail {
    uint64_t    zbt_magic;  /* for validation, endianness   */
    zio_cksum_t zbt_cksum;  /* 256-bit checksum     */
} zio_block_tail_t;

/*
 * Gang block headers are self-checksumming and contain an array
 * of block pointers.
 */
#define SPA_GANGBLOCKSIZE   SPA_MINBLOCKSIZE
#define SPA_GBH_NBLKPTRS    ((SPA_GANGBLOCKSIZE - \
    sizeof (zio_block_tail_t)) / sizeof (blkptr_t))
#define SPA_GBH_FILLER      ((SPA_GANGBLOCKSIZE - \
    sizeof (zio_block_tail_t) - \
    (SPA_GBH_NBLKPTRS * sizeof (blkptr_t))) /\
    sizeof (uint64_t))

#define ZIO_GET_DVA(zio)    (&(zio)->io_bp->blk_dva[(zio)->io_dva_index])
#define ZIO_GET_IOSIZE(zio) \
    (DVA_GET_GANG(ZIO_GET_DVA(zio)) ? \
    SPA_GANGBLOCKSIZE : BP_GET_PSIZE((zio)->io_bp))

typedef struct zio_gbh {
    blkptr_t        zg_blkptr[SPA_GBH_NBLKPTRS];
    uint64_t        zg_filler[SPA_GBH_FILLER];
    zio_block_tail_t    zg_tail;
} zio_gbh_phys_t;

enum zio_checksum {
    ZIO_CHECKSUM_INHERIT = 0,
    ZIO_CHECKSUM_ON,
    ZIO_CHECKSUM_OFF,
    ZIO_CHECKSUM_LABEL,
    ZIO_CHECKSUM_GANG_HEADER,
    ZIO_CHECKSUM_ZILOG,
    ZIO_CHECKSUM_FLETCHER_2,
    ZIO_CHECKSUM_FLETCHER_4,
    ZIO_CHECKSUM_SHA256,
    ZIO_CHECKSUM_FUNCTIONS
};

#define ZIO_CHECKSUM_ON_VALUE   ZIO_CHECKSUM_FLETCHER_2
#define ZIO_CHECKSUM_DEFAULT    ZIO_CHECKSUM_ON

enum zio_compress {
    ZIO_COMPRESS_INHERIT = 0,
    ZIO_COMPRESS_ON,
    ZIO_COMPRESS_OFF,
    ZIO_COMPRESS_LZJB,
    ZIO_COMPRESS_FUNCTIONS
};

#define ZIO_COMPRESS_ON_VALUE   ZIO_COMPRESS_LZJB
#define ZIO_COMPRESS_DEFAULT    ZIO_COMPRESS_OFF

#define ZIO_PRIORITY_NOW        (zio_priority_table[0])
#define ZIO_PRIORITY_SYNC_READ      (zio_priority_table[1])
#define ZIO_PRIORITY_SYNC_WRITE     (zio_priority_table[2])
#define ZIO_PRIORITY_ASYNC_READ     (zio_priority_table[3])
#define ZIO_PRIORITY_ASYNC_WRITE    (zio_priority_table[4])
#define ZIO_PRIORITY_FREE       (zio_priority_table[5])
#define ZIO_PRIORITY_CACHE_FILL     (zio_priority_table[6])
#define ZIO_PRIORITY_LOG_WRITE      (zio_priority_table[7])
#define ZIO_PRIORITY_RESILVER       (zio_priority_table[8])
#define ZIO_PRIORITY_SCRUB      (zio_priority_table[9])
#define ZIO_PRIORITY_TABLE_SIZE     10

#define ZIO_FLAG_MUSTSUCCEED        0x0000
#define ZIO_FLAG_CANFAIL        0x0001
#define ZIO_FLAG_FAILFAST       0x0002
#define ZIO_FLAG_CONFIG_HELD        0x0004

#define ZIO_FLAG_DONT_CACHE     0x0010
#define ZIO_FLAG_DONT_QUEUE     0x0020
#define ZIO_FLAG_DONT_PROPAGATE     0x0040
#define ZIO_FLAG_DONT_RETRY     0x0080

#define ZIO_FLAG_PHYSICAL       0x0100
#define ZIO_FLAG_IO_BYPASS      0x0200
#define ZIO_FLAG_IO_REPAIR      0x0400
#define ZIO_FLAG_SPECULATIVE        0x0800

#define ZIO_FLAG_RESILVER       0x1000
#define ZIO_FLAG_SCRUB          0x2000

#define ZIO_FLAG_GANG_INHERIT       \
    (ZIO_FLAG_CANFAIL |     \
    ZIO_FLAG_FAILFAST |     \
    ZIO_FLAG_CONFIG_HELD |      \
    ZIO_FLAG_DONT_RETRY |       \
    ZIO_FLAG_IO_REPAIR |        \
    ZIO_FLAG_SPECULATIVE |      \
    ZIO_FLAG_RESILVER |     \
    ZIO_FLAG_SCRUB)

#define ZIO_FLAG_VDEV_INHERIT       \
    (ZIO_FLAG_GANG_INHERIT |    \
    ZIO_FLAG_DONT_CACHE |       \
    ZIO_FLAG_PHYSICAL)

/*
 * We'll take the unused errno 'EBADE' (from the Convergent graveyard)
 * to indicate checksum errors.
 */
#define ECKSUM  EBADE

typedef struct zio zio_t;
typedef void zio_done_func_t(zio_t *zio);
typedef struct zio_transform zio_transform_t;

extern uint8_t zio_priority_table[ZIO_PRIORITY_TABLE_SIZE];
extern char *zio_type_name[ZIO_TYPES];

struct zio {
    /* Core information about this I/O */
    zio_t       *io_parent;
    zio_t       *io_root;
    spa_t       *io_spa;
    int     io_checksum;
    int     io_compress;
    int     io_dva_index;
    uint64_t    io_txg;
    blkptr_t    *io_bp;
    blkptr_t    io_bp_copy;
    zio_t       *io_child;
    zio_t       *io_sibling_prev;
    zio_t       *io_sibling_next;
    zio_transform_t *io_transform_stack;

    /* Callback info */
    zio_done_func_t *io_done;
    void        *io_private;
    blkptr_t    io_bp_orig;

    /* Data represented by this I/O */
    void        *io_data;
    uint64_t    io_size;

    /* Stuff for the vdev stack */
    vdev_t      *io_vd;
    void        *io_vsd;
    uint64_t    io_offset;
    uint64_t    io_deadline;
    uint64_t    io_timestamp;
    avl_node_t  io_offset_node;
    avl_node_t  io_deadline_node;
    avl_tree_t  *io_vdev_tree;
    zio_t       *io_delegate_list;
    zio_t       *io_delegate_next;
    zio_t       *io_retry_next;
    list_node_t io_pending;

    /* Internal pipeline state */
    int     io_flags;
    uint8_t     io_type;
    uint8_t     io_stage;
    uint8_t     io_stalled;
    uint8_t     io_priority;
    struct dk_callback io_dk_callback;
    int     io_cmd;
    int     io_retries;
    int     io_error;
    uint32_t    io_numerrors;
    uint32_t    io_pipeline;
    uint32_t    io_async_stages;
    uint64_t    io_children_notready;
    uint64_t    io_children_notdone;
    void        *io_waiter;
    kmutex_t    io_lock;
    kcondvar_t  io_cv;
};

extern zio_t *zio_null(zio_t *pio, spa_t *spa,
    zio_done_func_t *done, void *private, int flags);

extern zio_t *zio_root(spa_t *spa,
    zio_done_func_t *done, void *private, int flags);

extern zio_t *zio_read(zio_t *pio, spa_t *spa, blkptr_t *bp, void *data,
    uint64_t size, zio_done_func_t *done, void *private,
    int priority, int flags);

extern zio_t *zio_write(zio_t *pio, spa_t *spa, int checksum, int compress,
    uint64_t txg, blkptr_t *bp, void *data, uint64_t size,
    zio_done_func_t *done, void *private, int priority, int flags);

extern zio_t *zio_rewrite(zio_t *pio, spa_t *spa, int checksum,
    uint64_t txg, blkptr_t *bp, void *data, uint64_t size,
    zio_done_func_t *done, void *private, int priority, int flags);

extern zio_t *zio_free(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
    zio_done_func_t *done, void *private);

extern zio_t *zio_claim(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
    zio_done_func_t *done, void *private);

extern zio_t *zio_ioctl(zio_t *pio, spa_t *spa, vdev_t *vd, int cmd,
    zio_done_func_t *done, void *private, int priority, int flags);

extern zio_t *zio_read_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
    uint64_t size, void *data, int checksum,
    zio_done_func_t *done, void *private, int priority, int flags);

extern zio_t *zio_write_phys(zio_t *pio, vdev_t *vd, uint64_t offset,
    uint64_t size, void *data, int checksum,
    zio_done_func_t *done, void *private, int priority, int flags);

extern int zio_alloc_blk(spa_t *spa, int checksum, uint64_t size,
    blkptr_t *bp, uint64_t txg);
extern void zio_free_blk(spa_t *spa, blkptr_t *bp, uint64_t txg);

extern int zio_wait(zio_t *zio);
extern void zio_nowait(zio_t *zio);

extern void *zio_buf_alloc(size_t size);
extern void zio_buf_free(void *buf, size_t size);

/*
 * Move an I/O to the next stage of the pipeline and execute that stage.
 * There's no locking on io_stage because there's no legitimate way for
 * multiple threads to be attempting to process the same I/O.
 */
extern void zio_next_stage(zio_t *zio);
extern void zio_next_stage_async(zio_t *zio);
extern void zio_wait_children_done(zio_t *zio);

/*
 * Delegate I/O to a child vdev.
 */
extern zio_t *zio_vdev_child_io(zio_t *zio, blkptr_t *bp, vdev_t *vd,
    uint64_t offset, void *data, uint64_t size, int type, int priority,
    int flags, zio_done_func_t *done, void *private);

extern void zio_vdev_io_bypass(zio_t *zio);
extern void zio_vdev_io_reissue(zio_t *zio);
extern void zio_vdev_io_redone(zio_t *zio);

extern void zio_checksum_verified(zio_t *zio);
extern void zio_set_gang_verifier(zio_t *zio, zio_cksum_t *zcp);

extern uint8_t zio_checksum_select(uint8_t child, uint8_t parent);
extern uint8_t zio_compress_select(uint8_t child, uint8_t parent);

/*
 * Initial setup and teardown.
 */
extern void zio_init(void);
extern void zio_fini(void);

#ifdef  __cplusplus
}
#endif

#endif  /* _ZIO_H */