FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/include/sys/arc.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) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
     * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
     * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
     * Copyright (c) 2019, Allan Jude
     * Copyright (c) 2019, Klara Inc.
     */
    
    #ifndef _SYS_ARC_H
    #define _SYS_ARC_H
    
    #include <sys/zfs_context.h>
    
    #ifdef  __cplusplus
    extern "C" {
    #endif
    
    #include <sys/zio.h>
    #include <sys/dmu.h>
    #include <sys/spa.h>
    #include <sys/zfs_refcount.h>
    
    /*
     * Used by arc_flush() to inform arc_evict_state() that it should evict
     * all available buffers from the arc state being passed in.
     */
    #define ARC_EVICT_ALL   UINT64_MAX
    
    /*
     * ZFS gets very unhappy when the maximum ARC size is smaller than the maximum
     * block size and a larger block is written.  To leave some safety margin, we
     * limit the minimum for zfs_arc_max to the maximium transaction size.
     */
    #define MIN_ARC_MAX     DMU_MAX_ACCESS
    
    #define HDR_SET_LSIZE(hdr, x) do { \
            ASSERT(IS_P2ALIGNED(x, 1U << SPA_MINBLOCKSHIFT)); \
            (hdr)->b_lsize = ((x) >> SPA_MINBLOCKSHIFT); \
    } while (0)
    
    #define HDR_SET_PSIZE(hdr, x) do { \
            ASSERT(IS_P2ALIGNED((x), 1U << SPA_MINBLOCKSHIFT)); \
            (hdr)->b_psize = ((x) >> SPA_MINBLOCKSHIFT); \
    } while (0)
    
    #define HDR_GET_LSIZE(hdr)      ((hdr)->b_lsize << SPA_MINBLOCKSHIFT)
    #define HDR_GET_PSIZE(hdr)      ((hdr)->b_psize << SPA_MINBLOCKSHIFT)
    
    typedef struct arc_buf_hdr arc_buf_hdr_t;
    typedef struct arc_buf arc_buf_t;
    typedef struct arc_prune arc_prune_t;
    
    /*
     * Because the ARC can store encrypted data, errors (not due to bugs) may arise
     * while transforming data into its desired format - specifically, when
     * decrypting, the key may not be present, or the HMAC may not be correct
     * which signifies deliberate tampering with the on-disk state
     * (assuming that the checksum was correct). If any error occurs, the "buf"
     * parameter will be NULL.
     */
    typedef void arc_read_done_func_t(zio_t *zio, const zbookmark_phys_t *zb,
        const blkptr_t *bp, arc_buf_t *buf, void *priv);
    typedef void arc_write_done_func_t(zio_t *zio, arc_buf_t *buf, void *priv);
    typedef void arc_prune_func_t(int64_t bytes, void *priv);
    
    /* Shared module parameters */
    extern uint_t zfs_arc_average_blocksize;
    extern int l2arc_exclude_special;
    
    /* generic arc_done_func_t's which you can use */
    arc_read_done_func_t arc_bcopy_func;
    arc_read_done_func_t arc_getbuf_func;
    
    /* generic arc_prune_func_t wrapper for callbacks */
    struct arc_prune {
            arc_prune_func_t        *p_pfunc;
            void                    *p_private;
            uint64_t                p_adjust;
            list_node_t             p_node;
           zfs_refcount_t          p_refcnt;
   };
   
   typedef enum arc_strategy {
           ARC_STRATEGY_META_ONLY          = 0, /* Evict only meta data buffers */
           ARC_STRATEGY_META_BALANCED      = 1, /* Evict data buffers if needed */
   } arc_strategy_t;
   
   typedef enum arc_flags
   {
           /*
            * Public flags that can be passed into the ARC by external consumers.
            */
           ARC_FLAG_WAIT                   = 1 << 0,       /* perform sync I/O */
           ARC_FLAG_NOWAIT                 = 1 << 1,       /* perform async I/O */
           ARC_FLAG_PREFETCH               = 1 << 2,       /* I/O is a prefetch */
           ARC_FLAG_CACHED                 = 1 << 3,       /* I/O was in cache */
           ARC_FLAG_L2CACHE                = 1 << 4,       /* cache in L2ARC */
           ARC_FLAG_UNCACHED               = 1 << 5,       /* evict after use */
           ARC_FLAG_PRESCIENT_PREFETCH     = 1 << 6,       /* long min lifespan */
   
           /*
            * Private ARC flags.  These flags are private ARC only flags that
            * will show up in b_flags in the arc_hdr_buf_t. These flags should
            * only be set by ARC code.
            */
           ARC_FLAG_IN_HASH_TABLE          = 1 << 7,       /* buffer is hashed */
           ARC_FLAG_IO_IN_PROGRESS         = 1 << 8,       /* I/O in progress */
           ARC_FLAG_IO_ERROR               = 1 << 9,       /* I/O failed for buf */
           ARC_FLAG_INDIRECT               = 1 << 10,      /* indirect block */
           /* Indicates that block was read with ASYNC priority. */
           ARC_FLAG_PRIO_ASYNC_READ        = 1 << 11,
           ARC_FLAG_L2_WRITING             = 1 << 12,      /* write in progress */
           ARC_FLAG_L2_EVICTED             = 1 << 13,      /* evicted during I/O */
           ARC_FLAG_L2_WRITE_HEAD          = 1 << 14,      /* head of write list */
           /*
            * Encrypted or authenticated on disk (may be plaintext in memory).
            * This header has b_crypt_hdr allocated. Does not include indirect
            * blocks with checksums of MACs which will also have their X
            * (encrypted) bit set in the bp.
            */
           ARC_FLAG_PROTECTED              = 1 << 15,
           /* data has not been authenticated yet */
           ARC_FLAG_NOAUTH                 = 1 << 16,
           /* indicates that the buffer contains metadata (otherwise, data) */
           ARC_FLAG_BUFC_METADATA          = 1 << 17,
   
           /* Flags specifying whether optional hdr struct fields are defined */
           ARC_FLAG_HAS_L1HDR              = 1 << 18,
           ARC_FLAG_HAS_L2HDR              = 1 << 19,
   
           /*
            * Indicates the arc_buf_hdr_t's b_pdata matches the on-disk data.
            * This allows the l2arc to use the blkptr's checksum to verify
            * the data without having to store the checksum in the hdr.
            */
           ARC_FLAG_COMPRESSED_ARC         = 1 << 20,
           ARC_FLAG_SHARED_DATA            = 1 << 21,
   
           /*
            * Fail this arc_read() (with ENOENT) if the data is not already present
            * in cache.
            */
           ARC_FLAG_CACHED_ONLY            = 1 << 22,
   
           /*
            * Don't instantiate an arc_buf_t for arc_read_done.
            */
           ARC_FLAG_NO_BUF                 = 1 << 23,
   
           /*
            * The arc buffer's compression mode is stored in the top 7 bits of the
            * flags field, so these dummy flags are included so that MDB can
            * interpret the enum properly.
            */
           ARC_FLAG_COMPRESS_0             = 1 << 24,
           ARC_FLAG_COMPRESS_1             = 1 << 25,
           ARC_FLAG_COMPRESS_2             = 1 << 26,
           ARC_FLAG_COMPRESS_3             = 1 << 27,
           ARC_FLAG_COMPRESS_4             = 1 << 28,
           ARC_FLAG_COMPRESS_5             = 1 << 29,
           ARC_FLAG_COMPRESS_6             = 1 << 30
   
   } arc_flags_t;
   
   typedef enum arc_buf_flags {
           ARC_BUF_FLAG_SHARED             = 1 << 0,
           ARC_BUF_FLAG_COMPRESSED         = 1 << 1,
           /*
            * indicates whether this arc_buf_t is encrypted, regardless of
            * state on-disk
            */
           ARC_BUF_FLAG_ENCRYPTED          = 1 << 2
   } arc_buf_flags_t;
   
   struct arc_buf {
           arc_buf_hdr_t           *b_hdr;
           arc_buf_t               *b_next;
           void                    *b_data;
           arc_buf_flags_t         b_flags;
   };
   
   typedef enum arc_buf_contents {
           ARC_BUFC_INVALID,                       /* invalid type */
           ARC_BUFC_DATA,                          /* buffer contains data */
           ARC_BUFC_METADATA,                      /* buffer contains metadata */
           ARC_BUFC_NUMTYPES
   } arc_buf_contents_t;
   
   /*
    * The following breakdowns of arc_size exist for kstat only.
    */
   typedef enum arc_space_type {
           ARC_SPACE_DATA,
           ARC_SPACE_META,
           ARC_SPACE_HDRS,
           ARC_SPACE_L2HDRS,
           ARC_SPACE_DBUF,
           ARC_SPACE_DNODE,
           ARC_SPACE_BONUS,
           ARC_SPACE_ABD_CHUNK_WASTE,
           ARC_SPACE_NUMTYPES
   } arc_space_type_t;
   
   typedef enum arc_state_type {
           ARC_STATE_ANON,
           ARC_STATE_MRU,
           ARC_STATE_MRU_GHOST,
           ARC_STATE_MFU,
           ARC_STATE_MFU_GHOST,
           ARC_STATE_L2C_ONLY,
           ARC_STATE_UNCACHED,
           ARC_STATE_NUMTYPES
   } arc_state_type_t;
   
   typedef struct arc_buf_info {
           arc_state_type_t        abi_state_type;
           arc_buf_contents_t      abi_state_contents;
           uint32_t                abi_flags;
           uint32_t                abi_bufcnt;
           uint64_t                abi_size;
           uint64_t                abi_spa;
           uint64_t                abi_access;
           uint32_t                abi_mru_hits;
           uint32_t                abi_mru_ghost_hits;
           uint32_t                abi_mfu_hits;
           uint32_t                abi_mfu_ghost_hits;
           uint32_t                abi_l2arc_hits;
           uint32_t                abi_holds;
           uint64_t                abi_l2arc_dattr;
           uint64_t                abi_l2arc_asize;
           enum zio_compress       abi_l2arc_compress;
   } arc_buf_info_t;
   
   void arc_space_consume(uint64_t space, arc_space_type_t type);
   void arc_space_return(uint64_t space, arc_space_type_t type);
   boolean_t arc_is_metadata(arc_buf_t *buf);
   boolean_t arc_is_encrypted(arc_buf_t *buf);
   boolean_t arc_is_unauthenticated(arc_buf_t *buf);
   enum zio_compress arc_get_compression(arc_buf_t *buf);
   void arc_get_raw_params(arc_buf_t *buf, boolean_t *byteorder, uint8_t *salt,
       uint8_t *iv, uint8_t *mac);
   int arc_untransform(arc_buf_t *buf, spa_t *spa, const zbookmark_phys_t *zb,
       boolean_t in_place);
   void arc_convert_to_raw(arc_buf_t *buf, uint64_t dsobj, boolean_t byteorder,
       dmu_object_type_t ot, const uint8_t *salt, const uint8_t *iv,
       const uint8_t *mac);
   arc_buf_t *arc_alloc_buf(spa_t *spa, const void *tag, arc_buf_contents_t type,
       int32_t size);
   arc_buf_t *arc_alloc_compressed_buf(spa_t *spa, const void *tag,
       uint64_t psize, uint64_t lsize, enum zio_compress compression_type,
       uint8_t complevel);
   arc_buf_t *arc_alloc_raw_buf(spa_t *spa, const void *tag, uint64_t dsobj,
       boolean_t byteorder, const uint8_t *salt, const uint8_t *iv,
       const uint8_t *mac, dmu_object_type_t ot, uint64_t psize, uint64_t lsize,
       enum zio_compress compression_type, uint8_t complevel);
   uint8_t arc_get_complevel(arc_buf_t *buf);
   arc_buf_t *arc_loan_buf(spa_t *spa, boolean_t is_metadata, int size);
   arc_buf_t *arc_loan_compressed_buf(spa_t *spa, uint64_t psize, uint64_t lsize,
       enum zio_compress compression_type, uint8_t complevel);
   arc_buf_t *arc_loan_raw_buf(spa_t *spa, uint64_t dsobj, boolean_t byteorder,
       const uint8_t *salt, const uint8_t *iv, const uint8_t *mac,
       dmu_object_type_t ot, uint64_t psize, uint64_t lsize,
       enum zio_compress compression_type, uint8_t complevel);
   void arc_return_buf(arc_buf_t *buf, const void *tag);
   void arc_loan_inuse_buf(arc_buf_t *buf, const void *tag);
   void arc_buf_destroy(arc_buf_t *buf, const void *tag);
   void arc_buf_info(arc_buf_t *buf, arc_buf_info_t *abi, int state_index);
   uint64_t arc_buf_size(arc_buf_t *buf);
   uint64_t arc_buf_lsize(arc_buf_t *buf);
   void arc_buf_access(arc_buf_t *buf);
   void arc_release(arc_buf_t *buf, const void *tag);
   int arc_released(arc_buf_t *buf);
   void arc_buf_sigsegv(int sig, siginfo_t *si, void *unused);
   void arc_buf_freeze(arc_buf_t *buf);
   void arc_buf_thaw(arc_buf_t *buf);
   #ifdef ZFS_DEBUG
   int arc_referenced(arc_buf_t *buf);
   #else
   #define arc_referenced(buf) ((void) sizeof (buf), 0)
   #endif
   
   int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp,
       arc_read_done_func_t *done, void *priv, zio_priority_t priority,
       int flags, arc_flags_t *arc_flags, const zbookmark_phys_t *zb);
   zio_t *arc_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
       arc_buf_t *buf, boolean_t uncached, boolean_t l2arc, const zio_prop_t *zp,
       arc_write_done_func_t *ready, arc_write_done_func_t *child_ready,
       arc_write_done_func_t *physdone, arc_write_done_func_t *done,
       void *priv, zio_priority_t priority, int zio_flags,
       const zbookmark_phys_t *zb);
   
   arc_prune_t *arc_add_prune_callback(arc_prune_func_t *func, void *priv);
   void arc_remove_prune_callback(arc_prune_t *p);
   void arc_freed(spa_t *spa, const blkptr_t *bp);
   
   void arc_flush(spa_t *spa, boolean_t retry);
   void arc_tempreserve_clear(uint64_t reserve);
   int arc_tempreserve_space(spa_t *spa, uint64_t reserve, uint64_t txg);
   
   uint64_t arc_all_memory(void);
   uint64_t arc_default_max(uint64_t min, uint64_t allmem);
   uint64_t arc_target_bytes(void);
   void arc_set_limits(uint64_t);
   void arc_init(void);
   void arc_fini(void);
   
   /*
    * Level 2 ARC
    */
   
   void l2arc_add_vdev(spa_t *spa, vdev_t *vd);
   void l2arc_remove_vdev(vdev_t *vd);
   boolean_t l2arc_vdev_present(vdev_t *vd);
   void l2arc_rebuild_vdev(vdev_t *vd, boolean_t reopen);
   boolean_t l2arc_range_check_overlap(uint64_t bottom, uint64_t top,
       uint64_t check);
   void l2arc_init(void);
   void l2arc_fini(void);
   void l2arc_start(void);
   void l2arc_stop(void);
   void l2arc_spa_rebuild_start(spa_t *spa);
   
   #ifndef _KERNEL
   extern boolean_t arc_watch;
   #endif
   
   #ifdef  __cplusplus
   }
   #endif
   
   #endif /* _SYS_ARC_H */

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