FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/include/sys/vdev_draid.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 https://opensource.org/licenses/CDDL-1.0.
     * 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) 2016, Intel Corporation.
     * Copyright (c) 2020 by Lawrence Livermore National Security, LLC.
     */
    
    #ifndef _SYS_VDEV_DRAID_H
    #define _SYS_VDEV_DRAID_H
    
    #include <sys/types.h>
    #include <sys/abd.h>
    #include <sys/nvpair.h>
    #include <sys/zio.h>
    #include <sys/vdev_impl.h>
    #include <sys/vdev_raidz_impl.h>
    #include <sys/vdev.h>
    
    #ifdef  __cplusplus
    extern "C" {
    #endif
    
    /*
     * Constants required to generate and use dRAID permutations.
     */
    #define VDEV_DRAID_SEED                 0xd7a1d5eed
    #define VDEV_DRAID_MAX_MAPS             254
    #define VDEV_DRAID_ROWSHIFT             SPA_MAXBLOCKSHIFT
    #define VDEV_DRAID_ROWHEIGHT            (1ULL << VDEV_DRAID_ROWSHIFT)
    #define VDEV_DRAID_REFLOW_RESERVE       (2 * VDEV_DRAID_ROWHEIGHT)
    
    /*
     * dRAID permutation map.
     */
    typedef struct draid_map {
            uint64_t dm_children;   /* # of permutation columns */
            uint64_t dm_nperms;     /* # of permutation rows */
            uint64_t dm_seed;       /* dRAID map seed */
            uint64_t dm_checksum;   /* Checksum of generated map */
            uint8_t *dm_perms;      /* base permutation array */
    } draid_map_t;
    
    /*
     * dRAID configuration.
     */
    typedef struct vdev_draid_config {
            /*
             * Values read from the dRAID nvlist configuration.
             */
            uint64_t vdc_ndata;             /* # of data devices in group */
            uint64_t vdc_nparity;           /* # of parity devices in group */
            uint64_t vdc_nspares;           /* # of distributed spares */
            uint64_t vdc_children;          /* # of children */
            uint64_t vdc_ngroups;           /* # groups per slice */
    
            /*
             * Immutable derived constants.
             */
            uint8_t *vdc_perms;             /* permutation array */
            uint64_t vdc_nperms;            /* # of permutations */
            uint64_t vdc_groupwidth;        /* = data + parity */
            uint64_t vdc_ndisks;            /* = children - spares */
            uint64_t vdc_groupsz;           /* = groupwidth * DRAID_ROWSIZE */
            uint64_t vdc_devslicesz;        /* = (groupsz * groups) / ndisks */
    } vdev_draid_config_t;
    
    /*
     * Functions for handling dRAID permutation maps.
     */
    extern uint64_t vdev_draid_rand(uint64_t *);
    extern int vdev_draid_lookup_map(uint64_t, const draid_map_t **);
    extern int vdev_draid_generate_perms(const draid_map_t *, uint8_t **);
    
    /*
     * General dRAID support functions.
     */
    extern boolean_t vdev_draid_readable(vdev_t *, uint64_t);
    extern boolean_t vdev_draid_missing(vdev_t *, uint64_t, uint64_t, uint64_t);
    extern uint64_t vdev_draid_asize_to_psize(vdev_t *, uint64_t);
    extern void vdev_draid_map_alloc_empty(zio_t *, struct raidz_row *);
    extern int vdev_draid_map_verify_empty(zio_t *, struct raidz_row *);
   extern nvlist_t *vdev_draid_read_config_spare(vdev_t *);
   
   /* Functions for dRAID distributed spares. */
   extern vdev_t *vdev_draid_spare_get_child(vdev_t *, uint64_t);
   extern vdev_t *vdev_draid_spare_get_parent(vdev_t *);
   extern int vdev_draid_spare_create(nvlist_t *, vdev_t *, uint64_t *, uint64_t);
   
   #ifdef  __cplusplus
   }
   #endif
   
   #endif /* _SYS_VDEV_DRAID_H */

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