FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/zfs/ddt_zap.c

     /*
      * 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) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
     * Copyright (c) 2018 by Delphix. All rights reserved.
     */
    
    #include <sys/zfs_context.h>
    #include <sys/spa.h>
    #include <sys/zio.h>
    #include <sys/ddt.h>
    #include <sys/zap.h>
    #include <sys/dmu_tx.h>
    
    static const int ddt_zap_leaf_blockshift = 12;
    static const int ddt_zap_indirect_blockshift = 12;
    
    static int
    ddt_zap_create(objset_t *os, uint64_t *objectp, dmu_tx_t *tx, boolean_t prehash)
    {
            zap_flags_t flags = ZAP_FLAG_HASH64 | ZAP_FLAG_UINT64_KEY;
    
            if (prehash)
                    flags |= ZAP_FLAG_PRE_HASHED_KEY;
    
            *objectp = zap_create_flags(os, 0, flags, DMU_OT_DDT_ZAP,
                ddt_zap_leaf_blockshift, ddt_zap_indirect_blockshift,
                DMU_OT_NONE, 0, tx);
    
            return (*objectp == 0 ? SET_ERROR(ENOTSUP) : 0);
    }
    
    static int
    ddt_zap_destroy(objset_t *os, uint64_t object, dmu_tx_t *tx)
    {
            return (zap_destroy(os, object, tx));
    }
    
    static int
    ddt_zap_lookup(objset_t *os, uint64_t object, ddt_entry_t *dde)
    {
            uchar_t *cbuf;
            uint64_t one, csize;
            int error;
    
            cbuf = kmem_alloc(sizeof (dde->dde_phys) + 1, KM_SLEEP);
    
            error = zap_length_uint64(os, object, (uint64_t *)&dde->dde_key,
                DDT_KEY_WORDS, &one, &csize);
            if (error)
                    goto out;
    
            ASSERT(one == 1);
            ASSERT(csize <= (sizeof (dde->dde_phys) + 1));
    
            error = zap_lookup_uint64(os, object, (uint64_t *)&dde->dde_key,
                DDT_KEY_WORDS, 1, csize, cbuf);
            if (error)
                    goto out;
    
            ddt_decompress(cbuf, dde->dde_phys, csize, sizeof (dde->dde_phys));
    out:
            kmem_free(cbuf, sizeof (dde->dde_phys) + 1);
    
            return (error);
    }
    
    static void
    ddt_zap_prefetch(objset_t *os, uint64_t object, ddt_entry_t *dde)
    {
            (void) zap_prefetch_uint64(os, object, (uint64_t *)&dde->dde_key,
                DDT_KEY_WORDS);
    }
    
    static int
    ddt_zap_update(objset_t *os, uint64_t object, ddt_entry_t *dde, dmu_tx_t *tx)
    {
            uchar_t cbuf[sizeof (dde->dde_phys) + 1];
            uint64_t csize;
    
           csize = ddt_compress(dde->dde_phys, cbuf,
               sizeof (dde->dde_phys), sizeof (cbuf));
   
           return (zap_update_uint64(os, object, (uint64_t *)&dde->dde_key,
               DDT_KEY_WORDS, 1, csize, cbuf, tx));
   }
   
   static int
   ddt_zap_remove(objset_t *os, uint64_t object, ddt_entry_t *dde, dmu_tx_t *tx)
   {
           return (zap_remove_uint64(os, object, (uint64_t *)&dde->dde_key,
               DDT_KEY_WORDS, tx));
   }
   
   static int
   ddt_zap_walk(objset_t *os, uint64_t object, ddt_entry_t *dde, uint64_t *walk)
   {
           zap_cursor_t zc;
           zap_attribute_t za;
           int error;
   
           if (*walk == 0) {
                   /*
                    * We don't want to prefetch the entire ZAP object, because
                    * it can be enormous.  Also the primary use of DDT iteration
                    * is for scrubbing, in which case we will be issuing many
                    * scrub I/Os for each ZAP block that we read in, so
                    * reading the ZAP is unlikely to be the bottleneck.
                    */
                   zap_cursor_init_noprefetch(&zc, os, object);
           } else {
                   zap_cursor_init_serialized(&zc, os, object, *walk);
           }
           if ((error = zap_cursor_retrieve(&zc, &za)) == 0) {
                   uchar_t cbuf[sizeof (dde->dde_phys) + 1];
                   uint64_t csize = za.za_num_integers;
                   ASSERT(za.za_integer_length == 1);
                   error = zap_lookup_uint64(os, object, (uint64_t *)za.za_name,
                       DDT_KEY_WORDS, 1, csize, cbuf);
                   ASSERT(error == 0);
                   if (error == 0) {
                           ddt_decompress(cbuf, dde->dde_phys, csize,
                               sizeof (dde->dde_phys));
                           dde->dde_key = *(ddt_key_t *)za.za_name;
                   }
                   zap_cursor_advance(&zc);
                   *walk = zap_cursor_serialize(&zc);
           }
           zap_cursor_fini(&zc);
           return (error);
   }
   
   static int
   ddt_zap_count(objset_t *os, uint64_t object, uint64_t *count)
   {
           return (zap_count(os, object, count));
   }
   
   const ddt_ops_t ddt_zap_ops = {
           "zap",
           ddt_zap_create,
           ddt_zap_destroy,
           ddt_zap_lookup,
           ddt_zap_prefetch,
           ddt_zap_update,
           ddt_zap_remove,
           ddt_zap_walk,
           ddt_zap_count,
   };

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