dedup

data deduplication program
git clone git://git.2f30.org/dedup.git
Log | Files | Refs | README | LICENSE

commit e8056ddcaccd7972a5008983d9bc60a3a36498c5
parent 009a69939e6ce193b6bf6ab287aa007a4b8ab11e
Author: sin <sin@2f30.org>
Date:   Thu, 21 Feb 2019 10:24:44 +0000

Implement chunker interface

Diffstat:
MMakefile | 4++--
Achunker.c | 106+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Mdedup.c | 143++++++++++---------------------------------------------------------------------
Mdedup.h | 20++++++++++++++++++++
Ahash.c | 67+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 212 insertions(+), 128 deletions(-)

diff --git a/Makefile b/Makefile @@ -2,8 +2,8 @@ VERSION = 0.3 PREFIX = /usr/local MANPREFIX = $(PREFIX)/man BIN = dedup -SRC = $(BIN).c pack.c unpack.c -OBJ = $(BIN).o pack.o unpack.o +SRC = $(BIN).c chunker.c hash.c pack.c unpack.c +OBJ = $(BIN).o chunker.o hash.o pack.o unpack.o DISTFILES = $(SRC) LICENSE Makefile README arg.h $(BIN).1 dedup.h tree.h CFLAGS = -g -Wall diff --git a/chunker.c b/chunker.c @@ -0,0 +1,106 @@ +#include <err.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "dedup.h" + +struct chunker { + uint8_t *buf; + size_t size; + size_t pos; + int fd; +}; + +static size_t +get_chunk_size(struct chunker *chunker) +{ + uint8_t *bp; + size_t i; + uint32_t fp; + + /* buzhash should be at least WINSIZE */ + if (chunker->pos < WINSIZE) + return chunker->pos; + + bp = chunker->buf; + + /* + * To achieve better deduplication, we chunk blocks based on a + * recurring pattern occuring on the data stream. A fixed window + * of WINSIZE bytes is slid over the data, and a rolling hash is + * computed for this window. + * When the rolling hash matches a given pattern (see HASHMSK), + * the block is chunked at the end of that window, thus making + * WINSIZE the smallest possible block size. + */ + fp = buzh_init(bp, WINSIZE); + for (i = 0; i < chunker->pos - WINSIZE; i++) { + if (i > 0) + fp = buzh_update(fp, bp[i - 1], bp[WINSIZE + i - 1], + WINSIZE); + if ((fp & HASHMSK) == 0) + return i + WINSIZE; + } + return chunker->pos; +} + +struct chunker * +alloc_chunker(size_t size, int fd) +{ + struct chunker *chunker; + + chunker = malloc(sizeof(*chunker)); + if (chunker == NULL) + err(1, "malloc"); + + chunker->buf = malloc(size); + if (chunker->buf == NULL) + err(1, "malloc"); + chunker->size = size; + chunker->pos = 0; + chunker->fd = fd; + + return chunker; +} + +void +free_chunker(struct chunker *chunker) +{ + free(chunker->buf); + free(chunker); +} + +ssize_t +fill_chunker(struct chunker *chunker) +{ + uint8_t *bp; + ssize_t n; + + bp = &chunker->buf[chunker->pos]; + n = read(chunker->fd, bp, chunker->size - chunker->pos); + if (n < 0) + err(1, "read"); + chunker->pos += n; + return chunker->pos; +} + +void +drain_chunker(struct chunker *chunker, size_t chunk_size) +{ + uint8_t *src, *dst; + + src = &chunker->buf[chunk_size]; + dst = chunker->buf; + memmove(dst, src, chunker->pos - chunk_size); + chunker->pos -= chunk_size; +} + +uint8_t * +get_chunk(struct chunker *chunker, size_t *size) +{ + *size = get_chunk_size(chunker); + return chunker->buf; +} diff --git a/dedup.c b/dedup.c @@ -19,9 +19,6 @@ #define STOREF ".store" #define CACHEF ".cache" -#define BLKSIZE 4096 -#define WINSIZE 511 -#define HASHMSK ((1ul << 10) - 1) #define MSGSIZE 256 #define MDSIZE SHA256_DIGEST_LENGTH @@ -29,8 +26,6 @@ #define VER_MIN 1 #define VER_MAJ 0 -#define ROTL(x, y) (((x) << (y)) | ((x) >> (32 - (y)))) - enum { WALK_CONTINUE, WALK_STOP @@ -89,99 +84,6 @@ unsigned long long cache_hits; unsigned long long cache_misses; char *argv0; -/* - * Static table for use in buzhash algorithm. - * 256 * 32 bits randomly generated unique integers - * - * To get better pseudo-random results, there is exactly the same number - * of 0 and 1 spread amongst these integers. It means that there is - * exactly 50% chance that a XOR operation would flip all the bits in - * the hash. - */ -uint32_t buz[] = { - 0xbc9fa594,0x30a8f827,0xced627a7,0xdb46a745,0xcfa4a9e8,0x77cccb59,0xddb66276,0x3adc532f, - 0xfe8b67d3,0x8155b59e,0x0c893666,0x1d757009,0x17394ee4,0x85d94c07,0xcacd52da,0x076c6f79, - 0xead0a798,0x6c7ccb4a,0x2639a1b8,0x3aa5ae32,0x3e6218d2,0xb290d980,0xa5149521,0x4b426119, - 0xd3230fc7,0x677c1cc4,0x2b64603c,0x01fe92a8,0xbe358296,0xa7e7fac7,0xf509bf41,0x04b017ad, - 0xf900344c,0x8e14e202,0xb2a6e9b4,0x3db3c311,0x960286a8,0xf6bf0468,0xed54ec94,0xf358070c, - 0x6a4795dd,0x3f7b925c,0x5e13a060,0xfaecbafe,0x03c8bb55,0x8a56ba88,0x633e3b49,0xe036bbbe, - 0x1ed3dbb5,0x76e8ad74,0x79d346ab,0x44b4ccc4,0x71eb22d3,0xa1aa3f24,0x50e05b81,0xa3b450d3, - 0x7f5caffb,0xa1990650,0x54c44800,0xda134b65,0x72362eea,0xbd12b8e6,0xf7c99fdc,0x020d48c7, - 0x9d9c3d46,0x32b75615,0xe61923cf,0xadc09d8f,0xab11376b,0xd66fe4cd,0xb3b086b6,0xb8345b9f, - 0x59029667,0xae0e937c,0xcbd4d4ba,0x720bb3fb,0x5f7d2ca3,0xec24ba15,0x6b40109b,0xf0a54587, - 0x3acf9420,0x466e981d,0xc66dc124,0x150ef7b4,0xc3ce718e,0x136774f5,0x46684ab4,0xb4b490f0, - 0x26508a8b,0xf12febc8,0x4b99171b,0xfc373c84,0x339b5677,0x41703ff3,0x7cadbbd7,0x15ea24e2, - 0x7a2f9783,0xed6a383a,0x649eb072,0x79970941,0x2abd28ad,0x4375e00c,0x9df084f7,0x6fdeec6c, - 0x6619ac6d,0x7d256f4d,0x9b8e658a,0x3d7627e9,0xd5a98d45,0x15f84223,0x9b6acef5,0xf876be67, - 0xe3ae7089,0x84e2b64a,0x6818a969,0x86e9ba4e,0xa24a5b57,0x61570cf1,0xa5f8fc91,0x879d8383, - 0x91b13866,0x75e87961,0x16db8138,0x5a2ff6b8,0x8f664e9b,0x894e1496,0x88235c5b,0xcdb3b580, - 0xa2e80109,0xb0f88a82,0xd12cd340,0x93fbc37d,0xf4d1eb82,0xce42f309,0x16ffd2c2,0xb4dfef2b, - 0xb8b1a33e,0x4708a5e6,0xba66dd88,0xa9ec0da6,0x6f8ee2c9,0xad8b9993,0x1d6a25a8,0x1f3d08ce, - 0x149c04e7,0x5cd1fa51,0xb84c89c7,0xeced6f8c,0xe328b30f,0x084fa836,0x6d1bb1b7,0x94c78ea5, - 0x14973034,0xf1a1bcef,0x48b798d2,0xded9ca9e,0x5fd965d0,0x92544eb1,0x5e80f189,0xcbbf5e15, - 0x4d8121f0,0x5dd3b92f,0xd9ea98fb,0x2dbf5644,0x0fbcb9b7,0x20a1db53,0x7c3fcc98,0x36744fbd, - 0xced08954,0x8e7c5efe,0x3c5f6733,0x657477be,0x3630a02d,0x38bcbda0,0xb7702575,0x4a7f4bce, - 0x0e7660fe,0x4dcb91b5,0x4fd7ffd3,0x041821c1,0xa846a181,0xc8048e9e,0xd4b05072,0x986e0509, - 0xa00aaeeb,0x02e3526a,0x2fac4843,0xfa98e805,0x923ecd8d,0x395d9546,0x8674c3cd,0xae5a8a71, - 0x966dfe45,0x5c9ceba5,0x0830a1cf,0xa1750981,0x8f604480,0x28ea0c9a,0x0da12413,0x98b0b3c5, - 0xa21d473a,0x96ce4308,0xe9a1001b,0x8bbacb44,0x18bad3f4,0xe3121acb,0x46a9b45f,0x92cd9704, - 0xc1a7c619,0x3281e361,0x462e8c79,0x9e572f93,0x7239e5f0,0x67d8e6ba,0x13747ce3,0xf01ee64a, - 0xe7d0ae12,0xeea04088,0xe5b36767,0x17558eae,0x678ffbe6,0xe0bbc866,0x0c24adec,0xa9cbb869, - 0x3fd44ee1,0x9ca4ca06,0x04c0ef00,0x04589a21,0x9cf9c819,0x976f6ca1,0x8a30e66a,0x004d6f7e, - 0x384c8851,0x5bc97eb8,0xc6c49339,0x5aa386c7,0x74bdf8af,0x9b713750,0x4112f8c2,0x2895dae1, - 0xf576d905,0x9de98bce,0xb2b26bcd,0xd46707a0,0x147fbb46,0xa52c6e50,0xe43128fc,0x374ad964, - 0x8dfd4d53,0xc4d0c087,0x31dfb5ca,0xa44589b5,0x6b637e2e,0x663f6b45,0xd2d8baa0,0x1dac7e4c -}; - -/* Buzhash: https://en.wikipedia.org/wiki/Rolling_hash#Cyclic_polynomial */ -uint32_t -buzh_init(uint8_t *buf, size_t size) -{ - size_t i; - uint32_t fp; - - for (i = size - 1, fp = 0; i > 0; i--, buf++) - fp ^= ROTL(buz[*buf], i % 32); - - return fp ^ buz[*buf]; -} - -uint32_t -buzh_update(uint32_t fp, uint8_t in, uint8_t out, size_t size) -{ - return ROTL(fp, 1) ^ ROTL(buz[out], size % 32) ^ buz[in]; -} - -uint64_t -chunk_blk(uint8_t *buf, size_t size) -{ - size_t i; - uint32_t fp; - - /* buzhash should be at least WINSIZE */ - if (size < WINSIZE) - return size; - - /* - * To achieve better deduplication, we chunk blocks based on a - * recurring pattern occuring on the data stream. A fixed window - * of WINSIZE bytes is slid over the data, and a rolling hash is - * computed for this window. - * When the rolling hash matches a given pattern (see HASHMSK), - * the block is chunked at the end of that window, thus making - * WINSIZE the smallest possible block size. - */ - fp = buzh_init(buf, WINSIZE); - for (i = 0; i < size - WINSIZE; i++) { - if (i > 0) - fp = buzh_update(fp, buf[i - 1], buf[WINSIZE + i - 1], - WINSIZE); - if ((fp & HASHMSK) == 0) - return i + WINSIZE; - } - return size; -} - size_t comp_size(size_t size) { @@ -460,43 +362,33 @@ lookup_blk_desc(uint8_t *md, struct blk_desc *blk_desc) void dedup(int fd, char *msg) { - uint8_t *buf[2]; struct snapshot *snap; + struct chunker *chunker; + uint8_t *comp_buf; SHA256_CTX ctx; - ssize_t n, bufsize; + ssize_t n; - buf[0] = alloc_buf(BLKSIZE); - buf[1] = alloc_buf(comp_size(BLKSIZE)); snap = alloc_snap(); + chunker = alloc_chunker(BLKSIZE, fd); + comp_buf = alloc_buf(comp_size(BLKSIZE)); - bufsize = 0; SHA256_Init(&ctx); - while ((n = xread(fd, buf[0] + bufsize, BLKSIZE - bufsize)) > 0 || - bufsize > 0) { - + while ((n = fill_chunker(chunker)) > 0) { uint8_t md[MDSIZE]; struct blk_desc blk_desc; - size_t blksize, csize; - uint8_t *inp = buf[0]; /* input buf */ - uint8_t *outp = buf[1]; /* compressed buf */ + size_t chunk_size, csize; + uint8_t *chunkp; - if (n > 0) { - bufsize += n; - snaphdr.st.orig_size += n; - } + chunkp = get_chunk(chunker, &chunk_size); + SHA256_Update(&ctx, chunkp, chunk_size); - blksize = chunk_blk(inp, bufsize); - csize = comp(inp, outp, blksize, comp_size(BLKSIZE)); + csize = comp(chunkp, comp_buf, chunk_size, comp_size(BLKSIZE)); + hash_blk(comp_buf, csize, md); + snaphdr.st.orig_size += chunk_size; snaphdr.st.comp_size += csize; - hash_blk(outp, csize, md); - - /* Calculate file hash one block at a time */ - SHA256_Update(&ctx, inp, blksize); - snap = grow_snap(snap, snap->nr_blk_descs + 1); - if (lookup_blk_desc(md, &blk_desc) < 0) { struct cache_entry *ent; @@ -506,7 +398,7 @@ dedup(int fd, char *msg) snap->blk_desc[snap->nr_blk_descs++] = blk_desc; - append_blk(outp, &blk_desc); + append_blk(comp_buf, &blk_desc); ent = alloc_cache_entry(); ent->blk_desc = blk_desc; @@ -526,8 +418,7 @@ dedup(int fd, char *msg) cache_hits++; } - memmove(inp, inp + blksize, bufsize - blksize); - bufsize -= blksize; + drain_chunker(chunker, chunk_size); } if (snap->nr_blk_descs > 0) { @@ -546,9 +437,9 @@ dedup(int fd, char *msg) append_snap(snap); } + free(comp_buf); + free_chunker(chunker); free(snap); - free(buf[1]); - free(buf[0]); } int diff --git a/dedup.h b/dedup.h @@ -1,2 +1,22 @@ +#define BLKSIZE 4096 +#define WINSIZE 511 +#define HASHMSK ((1ul << 10) - 1) + +struct chunker; + +/* chunker.c */ +struct chunker *alloc_chunker(size_t size, int fd); +void free_chunker(struct chunker *chunker); +ssize_t fill_chunker(struct chunker *chunker); +void drain_chunker(struct chunker *chunker, size_t n); +uint8_t *get_chunk(struct chunker *chunker, size_t *size); + +/* hash.c */ +uint32_t buzh_init(uint8_t *buf, size_t size); +uint32_t buzh_update(uint32_t fp, uint8_t in, uint8_t out, size_t size); + +/* pack.c */ int pack(unsigned char *dst, char *fmt, ...); + +/* unpack.c */ int unpack(unsigned char *src, char *fmt, ...); diff --git a/hash.c b/hash.c @@ -0,0 +1,67 @@ +#include <stddef.h> +#include <stdint.h> + +#define ROTL(x, y) (((x) << (y)) | ((x) >> (32 - (y)))) + +/* + * Static table for use in buzhash algorithm. + * 256 * 32 bits randomly generated unique integers + * + * To get better pseudo-random results, there is exactly the same number + * of 0 and 1 spread amongst these integers. It means that there is + * exactly 50% chance that a XOR operation would flip all the bits in + * the hash. + */ +static uint32_t buz[] = { + 0xbc9fa594,0x30a8f827,0xced627a7,0xdb46a745,0xcfa4a9e8,0x77cccb59,0xddb66276,0x3adc532f, + 0xfe8b67d3,0x8155b59e,0x0c893666,0x1d757009,0x17394ee4,0x85d94c07,0xcacd52da,0x076c6f79, + 0xead0a798,0x6c7ccb4a,0x2639a1b8,0x3aa5ae32,0x3e6218d2,0xb290d980,0xa5149521,0x4b426119, + 0xd3230fc7,0x677c1cc4,0x2b64603c,0x01fe92a8,0xbe358296,0xa7e7fac7,0xf509bf41,0x04b017ad, + 0xf900344c,0x8e14e202,0xb2a6e9b4,0x3db3c311,0x960286a8,0xf6bf0468,0xed54ec94,0xf358070c, + 0x6a4795dd,0x3f7b925c,0x5e13a060,0xfaecbafe,0x03c8bb55,0x8a56ba88,0x633e3b49,0xe036bbbe, + 0x1ed3dbb5,0x76e8ad74,0x79d346ab,0x44b4ccc4,0x71eb22d3,0xa1aa3f24,0x50e05b81,0xa3b450d3, + 0x7f5caffb,0xa1990650,0x54c44800,0xda134b65,0x72362eea,0xbd12b8e6,0xf7c99fdc,0x020d48c7, + 0x9d9c3d46,0x32b75615,0xe61923cf,0xadc09d8f,0xab11376b,0xd66fe4cd,0xb3b086b6,0xb8345b9f, + 0x59029667,0xae0e937c,0xcbd4d4ba,0x720bb3fb,0x5f7d2ca3,0xec24ba15,0x6b40109b,0xf0a54587, + 0x3acf9420,0x466e981d,0xc66dc124,0x150ef7b4,0xc3ce718e,0x136774f5,0x46684ab4,0xb4b490f0, + 0x26508a8b,0xf12febc8,0x4b99171b,0xfc373c84,0x339b5677,0x41703ff3,0x7cadbbd7,0x15ea24e2, + 0x7a2f9783,0xed6a383a,0x649eb072,0x79970941,0x2abd28ad,0x4375e00c,0x9df084f7,0x6fdeec6c, + 0x6619ac6d,0x7d256f4d,0x9b8e658a,0x3d7627e9,0xd5a98d45,0x15f84223,0x9b6acef5,0xf876be67, + 0xe3ae7089,0x84e2b64a,0x6818a969,0x86e9ba4e,0xa24a5b57,0x61570cf1,0xa5f8fc91,0x879d8383, + 0x91b13866,0x75e87961,0x16db8138,0x5a2ff6b8,0x8f664e9b,0x894e1496,0x88235c5b,0xcdb3b580, + 0xa2e80109,0xb0f88a82,0xd12cd340,0x93fbc37d,0xf4d1eb82,0xce42f309,0x16ffd2c2,0xb4dfef2b, + 0xb8b1a33e,0x4708a5e6,0xba66dd88,0xa9ec0da6,0x6f8ee2c9,0xad8b9993,0x1d6a25a8,0x1f3d08ce, + 0x149c04e7,0x5cd1fa51,0xb84c89c7,0xeced6f8c,0xe328b30f,0x084fa836,0x6d1bb1b7,0x94c78ea5, + 0x14973034,0xf1a1bcef,0x48b798d2,0xded9ca9e,0x5fd965d0,0x92544eb1,0x5e80f189,0xcbbf5e15, + 0x4d8121f0,0x5dd3b92f,0xd9ea98fb,0x2dbf5644,0x0fbcb9b7,0x20a1db53,0x7c3fcc98,0x36744fbd, + 0xced08954,0x8e7c5efe,0x3c5f6733,0x657477be,0x3630a02d,0x38bcbda0,0xb7702575,0x4a7f4bce, + 0x0e7660fe,0x4dcb91b5,0x4fd7ffd3,0x041821c1,0xa846a181,0xc8048e9e,0xd4b05072,0x986e0509, + 0xa00aaeeb,0x02e3526a,0x2fac4843,0xfa98e805,0x923ecd8d,0x395d9546,0x8674c3cd,0xae5a8a71, + 0x966dfe45,0x5c9ceba5,0x0830a1cf,0xa1750981,0x8f604480,0x28ea0c9a,0x0da12413,0x98b0b3c5, + 0xa21d473a,0x96ce4308,0xe9a1001b,0x8bbacb44,0x18bad3f4,0xe3121acb,0x46a9b45f,0x92cd9704, + 0xc1a7c619,0x3281e361,0x462e8c79,0x9e572f93,0x7239e5f0,0x67d8e6ba,0x13747ce3,0xf01ee64a, + 0xe7d0ae12,0xeea04088,0xe5b36767,0x17558eae,0x678ffbe6,0xe0bbc866,0x0c24adec,0xa9cbb869, + 0x3fd44ee1,0x9ca4ca06,0x04c0ef00,0x04589a21,0x9cf9c819,0x976f6ca1,0x8a30e66a,0x004d6f7e, + 0x384c8851,0x5bc97eb8,0xc6c49339,0x5aa386c7,0x74bdf8af,0x9b713750,0x4112f8c2,0x2895dae1, + 0xf576d905,0x9de98bce,0xb2b26bcd,0xd46707a0,0x147fbb46,0xa52c6e50,0xe43128fc,0x374ad964, + 0x8dfd4d53,0xc4d0c087,0x31dfb5ca,0xa44589b5,0x6b637e2e,0x663f6b45,0xd2d8baa0,0x1dac7e4c +}; + +/* Buzhash: https://en.wikipedia.org/wiki/Rolling_hash#Cyclic_polynomial */ +uint32_t +buzh_init(uint8_t *buf, size_t size) +{ + size_t i; + uint32_t fp; + + for (i = size - 1, fp = 0; i > 0; i--, buf++) + fp ^= ROTL(buz[*buf], i % 32); + + return fp ^ buz[*buf]; +} + +uint32_t +buzh_update(uint32_t fp, uint8_t in, uint8_t out, size_t size) +{ + return ROTL(fp, 1) ^ ROTL(buz[out], size % 32) ^ buz[in]; +}