1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #include <sys/zfs_context.h> 29 #include <sys/compress.h> 30 #include <sys/spa.h> 31 #include <sys/zio.h> 32 #include <sys/zio_compress.h> 33 34 /* 35 * Compression vectors. 36 */ 37 38 zio_compress_info_t zio_compress_table[ZIO_COMPRESS_FUNCTIONS] = { 39 {NULL, NULL, "inherit"}, 40 {NULL, NULL, "on"}, 41 {NULL, NULL, "uncompressed"}, 42 {lzjb_compress, lzjb_decompress, "lzjb"}, 43 {NULL, NULL, "empty"}, 44 }; 45 46 uint8_t 47 zio_compress_select(uint8_t child, uint8_t parent) 48 { 49 ASSERT(child < ZIO_COMPRESS_FUNCTIONS); 50 ASSERT(parent < ZIO_COMPRESS_FUNCTIONS); 51 ASSERT(parent != ZIO_COMPRESS_INHERIT && parent != ZIO_COMPRESS_ON); 52 53 if (child == ZIO_COMPRESS_INHERIT) 54 return (parent); 55 56 if (child == ZIO_COMPRESS_ON) 57 return (ZIO_COMPRESS_ON_VALUE); 58 59 return (child); 60 } 61 62 int 63 zio_compress_data(int cpfunc, void *src, uint64_t srcsize, void **destp, 64 uint64_t *destsizep, uint64_t *destbufsizep) 65 { 66 uint64_t *word, *word_end; 67 uint64_t ciosize, gapsize, destbufsize; 68 zio_compress_info_t *ci = &zio_compress_table[cpfunc]; 69 char *dest; 70 uint_t allzero; 71 72 ASSERT((uint_t)cpfunc < ZIO_COMPRESS_FUNCTIONS); 73 ASSERT((uint_t)cpfunc == ZIO_COMPRESS_EMPTY || ci->ci_compress != NULL); 74 75 /* 76 * If the data is all zeroes, we don't even need to allocate 77 * a block for it. We indicate this by setting *destsizep = 0. 78 */ 79 allzero = 1; 80 word = src; 81 word_end = (uint64_t *)(uintptr_t)((uintptr_t)word + srcsize); 82 while (word < word_end) { 83 if (*word++ != 0) { 84 allzero = 0; 85 break; 86 } 87 } 88 if (allzero) { 89 *destp = NULL; 90 *destsizep = 0; 91 *destbufsizep = 0; 92 return (1); 93 } 94 95 if (cpfunc == ZIO_COMPRESS_EMPTY) 96 return (0); 97 98 /* Compress at least 12.5% */ 99 destbufsize = P2ALIGN(srcsize - (srcsize >> 3), SPA_MINBLOCKSIZE); 100 if (destbufsize == 0) 101 return (0); 102 dest = zio_buf_alloc(destbufsize); 103 104 ciosize = ci->ci_compress(src, dest, (size_t)srcsize, 105 (size_t)destbufsize); 106 if (ciosize > destbufsize) { 107 zio_buf_free(dest, destbufsize); 108 return (0); 109 } 110 111 /* Cool. We compressed at least as much as we were hoping to. */ 112 113 /* For security, make sure we don't write random heap crap to disk */ 114 gapsize = P2ROUNDUP(ciosize, SPA_MINBLOCKSIZE) - ciosize; 115 if (gapsize != 0) { 116 bzero(dest + ciosize, gapsize); 117 ciosize += gapsize; 118 } 119 120 ASSERT3U(ciosize, <=, destbufsize); 121 ASSERT(P2PHASE(ciosize, SPA_MINBLOCKSIZE) == 0); 122 *destp = dest; 123 *destsizep = ciosize; 124 *destbufsizep = destbufsize; 125 126 return (1); 127 } 128 129 int 130 zio_decompress_data(int cpfunc, void *src, uint64_t srcsize, 131 void *dest, uint64_t destsize) 132 { 133 ASSERT((uint_t)cpfunc < ZIO_COMPRESS_FUNCTIONS); 134 135 return (zio_compress_table[cpfunc].ci_decompress(src, dest, 136 srcsize, destsize)); 137 } 138