commit e8056ddcaccd7972a5008983d9bc60a3a36498c5
parent 009a69939e6ce193b6bf6ab287aa007a4b8ab11e
Author: sin <sin@2f30.org>
Date: Thu, 21 Feb 2019 10:24:44 +0000
Implement chunker interface
Diffstat:
| M | Makefile | | | 4 | ++-- |
| A | chunker.c | | | 106 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| M | dedup.c | | | 143 | ++++++++++--------------------------------------------------------------------- |
| M | dedup.h | | | 20 | ++++++++++++++++++++ |
| A | hash.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];
+}
