Reduce memory consumption and improve performance in dedupe

Re-introduce crc64 for dedup blocks to avoid wasted memcpy-s
Restructe block array to be an array of pointers allocated on demand
Fix a corner case issue when splitting chunks at a dedup boundary
This commit is contained in:
Moinak Ghosh 2012-08-17 11:03:02 +05:30
parent 55d0485d34
commit 2dadf411fa
4 changed files with 129 additions and 114 deletions

View file

@ -72,8 +72,8 @@ COMPILE = gcc -m64 -g -msse3 -c
COMPILE_cpp = g++ -m64 -g -msse3 -c
VEC_FLAGS =
LOOP_OPTFLAGS =
GEN_OPT = -O
RABIN_OPT = -O
GEN_OPT = -O -fno-omit-frame-pointer
RABIN_OPT = -O -fno-omit-frame-pointer
else
GEN_OPT = -O3
RABIN_OPT = -O2

View file

@ -65,9 +65,19 @@
#include <allocator.h>
#include <utils.h>
#include <pthread.h>
#include <arpa/nameser_compat.h>
#include <crc_macros.h>
#include "rabin_polynomial.h"
#if BYTE_ORDER == BIG_ENDIAN
# define A1(x) ((x) >> 56)
#else
# define A1 A
#endif
extern const uint64_t lzma_crc64_table[4][256];
extern int lzma_init(void **data, int *level, ssize_t chunksize);
extern int lzma_compress(void *src, size_t srclen, void *dst,
size_t *destlen, int level, uchar_t chdr, void *data);
@ -80,8 +90,6 @@ extern bsize_t get_bsdiff_sz(u_char *pbuf);
extern int bspatch(u_char *pbuf, u_char *old, bsize_t oldsize, u_char *new,
bsize_t *_newsize);
uint32_t rabin_polynomial_max_block_size = RAB_POLYNOMIAL_MAX_BLOCK_SIZE;
static pthread_mutex_t init_lock = PTHREAD_MUTEX_INITIALIZER;
uint64_t ir[256];
static int inited = 0;
@ -99,7 +107,7 @@ rabin_context_t *
create_rabin_context(uint64_t chunksize, uint64_t real_chunksize, const char *algo, int delta_flag) {
rabin_context_t *ctx;
unsigned char *current_window_data;
uint32_t blknum;
uint32_t i;
/*
* Pre-compute a table of irreducible polynomial evaluations for each
@ -107,20 +115,19 @@ create_rabin_context(uint64_t chunksize, uint64_t real_chunksize, const char *al
*/
pthread_mutex_lock(&init_lock);
if (!inited) {
int i;
int term;
int term, j;
uint64_t val;
for (blknum = 0; blknum < 256; blknum++) {
for (j = 0; j < 256; j++) {
term = 1;
val = 0;
for (i=0; i<RAB_POLYNOMIAL_WIN_SIZE; i++) {
if (term & FP_POLY) {
val = (val << 1) + blknum;
val = (val << 1) + j;
}
term <<= 1;
}
ir[blknum] = val;
ir[j] = val;
}
inited = 1;
}
@ -171,11 +178,11 @@ create_rabin_context(uint64_t chunksize, uint64_t real_chunksize, const char *al
}
ctx->fp_mask = ctx->rabin_avg_block_mask | ctx->rabin_poly_avg_block_size;
blknum = chunksize / ctx->rabin_poly_min_block_size;
ctx->blknum = chunksize / ctx->rabin_poly_min_block_size;
if (chunksize % ctx->rabin_poly_min_block_size)
blknum++;
ctx->blknum++;
if (blknum > RABIN_MAX_BLOCKS) {
if (ctx->blknum > RABIN_MAX_BLOCKS) {
fprintf(stderr, "Chunk size too large for dedup.\n");
destroy_rabin_context(ctx);
return (NULL);
@ -183,8 +190,8 @@ create_rabin_context(uint64_t chunksize, uint64_t real_chunksize, const char *al
current_window_data = slab_alloc(NULL, RAB_POLYNOMIAL_WIN_SIZE);
ctx->blocks = NULL;
if (real_chunksize > 0) {
ctx->blocks = (rabin_blockentry_t *)slab_alloc(NULL,
blknum * sizeof (rabin_blockentry_t));
ctx->blocks = (rabin_blockentry_t **)slab_calloc(NULL,
ctx->blknum, sizeof (rabin_blockentry_t *));
}
if(ctx == NULL || current_window_data == NULL || (ctx->blocks == NULL && real_chunksize > 0)) {
fprintf(stderr,
@ -232,8 +239,14 @@ void
destroy_rabin_context(rabin_context_t *ctx)
{
if (ctx) {
uint32_t i;
if (ctx->current_window_data) slab_free(NULL, ctx->current_window_data);
if (ctx->blocks) slab_free(NULL, ctx->blocks);
if (ctx->blocks) {
for (i=0; i<ctx->blknum && ctx->blocks[i] != NULL; i++) {
slab_free(NULL, ctx->blocks[i]);
}
slab_free(NULL, ctx->blocks);
}
if (ctx->lzma_data) lzma_deinit(&(ctx->lzma_data));
slab_free(NULL, ctx);
}
@ -245,8 +258,8 @@ destroy_rabin_context(rabin_context_t *ctx)
static int
cmpblks(const void *a, const void *b)
{
rabin_blockentry_t *a1 = (rabin_blockentry_t *)a;
rabin_blockentry_t *b1 = (rabin_blockentry_t *)b;
rabin_blockentry_t *a1 = *((rabin_blockentry_t **)a);
rabin_blockentry_t *b1 = *((rabin_blockentry_t **)b);
if (a1->cksum_n_offset < b1->cksum_n_offset) {
return (-1);
@ -283,6 +296,7 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
uint64_t *fplist;
uint32_t len1, fpos[2], cur_sketch2;
uint32_t *charcounts, byts;
uint64_t crc;
if (rabin_pos == NULL) {
/*
@ -305,6 +319,7 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
j = 0;
cur_sketch = 0;
cur_sketch2 = 0;
crc = 0;
/*
* If rabin_pos is non-zero then we are being asked to scan for the last rabin boundary
@ -314,7 +329,8 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
* !!!NOTE!!!: Code duplication below for performance.
*/
if (rabin_pos) {
offset = *size - RAB_POLYNOMIAL_MAX_BLOCK_SIZE;
offset = *size - ctx->rabin_poly_max_block_size;
length = 0;
for (i=offset; i<*size; i++) {
uchar_t cur_byte = buf1[i];
uint64_t pushed_out = ctx->current_window_data[ctx->window_pos];
@ -328,10 +344,9 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
length++;
if (length < ctx->rabin_poly_min_block_size) continue;
// If we hit our special value or reached the max block size update block offset
if ((cur_pos_checksum & ctx->rabin_avg_block_mask) == ctx->rabin_break_patt ||
length >= rabin_polynomial_max_block_size) {
last_offset = i+1;
// If we hit our special value update block offset
if ((cur_pos_checksum & ctx->rabin_avg_block_mask) == ctx->rabin_break_patt) {
last_offset = i;
length = 0;
}
}
@ -358,6 +373,7 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
cur_roll_checksum = (cur_roll_checksum << 1) + cur_byte;
cur_roll_checksum -= (pushed_out << RAB_POLYNOMIAL_WIN_SIZE);
cur_pos_checksum = cur_roll_checksum ^ ir[pushed_out];
crc = lzma_crc64_table[0][cur_byte ^ A1(crc)] ^ S8(crc);
/*
* Compute a super sketch value of the block. We store a sum of relative
@ -436,16 +452,19 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
// If we hit our special value or reached the max block size update block offset
if ((cur_pos_checksum & ctx->rabin_avg_block_mask) == ctx->rabin_break_patt ||
length >= rabin_polynomial_max_block_size) {
ctx->blocks[blknum].offset = last_offset;
ctx->blocks[blknum].index = blknum; // Need to store for sorting
ctx->blocks[blknum].length = length;
ctx->blocks[blknum].ref = 0;
ctx->blocks[blknum].similar = 0;
length >= ctx->rabin_poly_max_block_size) {
if (ctx->blocks[blknum] == 0)
ctx->blocks[blknum] = (rabin_blockentry_t *)slab_alloc(NULL, sizeof (rabin_blockentry_t));
ctx->blocks[blknum]->offset = last_offset;
ctx->blocks[blknum]->index = blknum; // Need to store for sorting
ctx->blocks[blknum]->length = length;
ctx->blocks[blknum]->ref = 0;
ctx->blocks[blknum]->similar = 0;
ctx->blocks[blknum]->crc = crc;
// Accumulate the 2 sketch values into a combined similarity checksum
ctx->blocks[blknum].cksum_n_offset = (cur_sketch + cur_sketch2) / 2;
ctx->blocks[blknum].mean_n_length = cur_sketch / j;
ctx->blocks[blknum]->cksum_n_offset = (cur_sketch + cur_sketch2) / 2;
ctx->blocks[blknum]->mean_n_length = cur_sketch / j;
memset(fplist, 0, fplist_sz);
fpos[0] = 0;
len1 = 0;
@ -455,48 +474,50 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
length = 0;
j = 0;
cur_sketch2 = 0;
crc = 0;
}
}
DEBUG_STAT_EN(printf("Original size: %lld, blknum: %u\n", *size, blknum));
// If we found at least a few chunks, perform dedup.
if (blknum > 2) {
uint64_t prev_cksum;
uint32_t blk, prev_length;
uint32_t blk, prev_index, prev_length;
ssize_t pos, matchlen, pos1;
int valid = 1;
char *tmp, *prev_offset;
uint32_t *blkarr, *trans, *rabin_index, prev_index, prev_blk;
char *tmp;
uint32_t *blkarr, *trans, *rabin_index;
ssize_t rabin_index_sz;
rabin_blockentry_t *prev;
DEBUG_STAT_EN(uint32_t delta_calls, delta_fails);
DEBUG_STAT_EN(delta_calls = 0);
DEBUG_STAT_EN(delta_fails = 0);
// Insert the last left-over trailing bytes, if any, into a block.
if (last_offset < *size) {
ctx->blocks[blknum].offset = last_offset;
ctx->blocks[blknum].index = blknum;
ctx->blocks[blknum].length = *size - last_offset;
ctx->blocks[blknum].ref = 0;
ctx->blocks[blknum].similar = 0;
if (ctx->blocks[blknum] == 0)
ctx->blocks[blknum] = (rabin_blockentry_t *)slab_alloc(NULL, sizeof (rabin_blockentry_t));
ctx->blocks[blknum]->offset = last_offset;
ctx->blocks[blknum]->index = blknum;
ctx->blocks[blknum]->length = *size - last_offset;
ctx->blocks[blknum]->ref = 0;
ctx->blocks[blknum]->similar = 0;
j = (j > 0 ? j:1);
ctx->blocks[blknum].cksum_n_offset = (cur_sketch + cur_sketch2) / 2;
ctx->blocks[blknum].mean_n_length = cur_sketch / j;
ctx->blocks[blknum]->cksum_n_offset = (cur_sketch + cur_sketch2) / 2;
ctx->blocks[blknum]->mean_n_length = cur_sketch / j;
ctx->blocks[blknum]->crc = crc;
blknum++;
last_offset = *size;
}
rabin_index_sz = (ssize_t)blknum * RABIN_ENTRY_SIZE;
prev_cksum = 0;
prev_length = 0;
prev_offset = 0;
/*
* Now sort the block array based on checksums. This will bring virtually
* all similar block entries together. Effectiveness depends on how strong
* our checksum is. We are using a maximal super-sketch value.
*/
qsort(ctx->blocks, blknum, sizeof (rabin_blockentry_t), cmpblks);
qsort(ctx->blocks, blknum, sizeof (rabin_blockentry_t *), cmpblks);
rabin_index = (uint32_t *)(ctx->cbuf + RABIN_HDR_SIZE);
/*
@ -518,53 +539,44 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
* blocks. This helps in non-duplicate block merging later.
*/
for (blk = 0; blk < blknum; blk++) {
blkarr[ctx->blocks[blk].index] = blk;
blkarr[ctx->blocks[blk]->index] = blk;
if (blk > 0 && ctx->blocks[blk].cksum_n_offset == prev_cksum &&
ctx->blocks[blk].length == prev_length &&
memcmp(prev_offset, buf1 + ctx->blocks[blk].offset, prev_length) == 0) {
ctx->blocks[blk].similar = SIMILAR_EXACT;
ctx->blocks[blk].index = prev_index;
ctx->blocks[prev_blk].ref = 1;
matchlen += prev_length;
if (blk > 0 && ctx->blocks[blk]->cksum_n_offset == prev->cksum_n_offset &&
ctx->blocks[blk]->length == prev->length &&
ctx->blocks[blk]->crc == prev->crc &&
memcmp(buf1 + prev->offset, buf1 + ctx->blocks[blk]->offset,
prev->length) == 0)
{
ctx->blocks[blk]->similar = SIMILAR_EXACT;
ctx->blocks[blk]->index = prev->index;
prev->ref = 1;
matchlen += prev->length;
continue;
}
prev_offset = buf1 + ctx->blocks[blk].offset;
prev_cksum = ctx->blocks[blk].cksum_n_offset;
prev_length = ctx->blocks[blk].length;
prev_index = ctx->blocks[blk].index;
prev_blk = blk;
prev = ctx->blocks[blk];
}
prev = NULL;
if (ctx->delta_flag) {
uint64_t prev_mean;
prev_mean = 0;
prev_cksum = 0;
prev_length = 0;
for (blk = 0; blk < blknum; blk++) {
if (ctx->blocks[blk].similar) continue;
if (ctx->blocks[blk]->similar) continue;
/*
* Compare blocks for similarity.
* Note: Block list by now is sorted by length as well.
*/
if (blk > 0 && ctx->blocks[blk].ref == 0 &&
ctx->blocks[blk].cksum_n_offset == prev_cksum &&
ctx->blocks[blk].length - prev_length < 512 &&
ctx->blocks[blk].mean_n_length == prev_mean
if (prev != NULL && ctx->blocks[blk]->ref == 0 &&
ctx->blocks[blk]->cksum_n_offset == prev->cksum_n_offset &&
ctx->blocks[blk]->length - prev->length < 512 &&
ctx->blocks[blk]->mean_n_length == prev->mean_n_length
) {
ctx->blocks[blk].index = prev_index;
ctx->blocks[blk].similar = SIMILAR_PARTIAL;
ctx->blocks[prev_blk].ref = 1;
matchlen += (prev_length>>1);
ctx->blocks[blk]->index = prev->index;
ctx->blocks[blk]->similar = SIMILAR_PARTIAL;
prev->ref = 1;
matchlen += (prev->length>>1);
continue;
}
prev_cksum = ctx->blocks[blk].cksum_n_offset;
prev_length = ctx->blocks[blk].length;
prev_index = ctx->blocks[blk].index;
prev_mean = ctx->blocks[blk].mean_n_length;
prev_blk = blk;
prev = ctx->blocks[blk];
}
}
if (matchlen < rabin_index_sz) {
@ -585,7 +597,7 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
for (blk = 0; blk < blknum; blk++) {
rabin_blockentry_t *be;
be = &(ctx->blocks[blkarr[blk]]);
be = ctx->blocks[blkarr[blk]];
if (be->similar == 0) {
/*
* Update Index entry with the length. Also try to merge runs
@ -599,7 +611,7 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
prev_length = be->length;
}
rabin_index[pos] = be->length;
ctx->blocks[pos].cksum_n_offset = be->offset;
ctx->blocks[pos]->cksum_n_offset = be->offset;
trans[blk] = pos;
pos++;
} else {
@ -607,7 +619,7 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
prev_index = 0;
prev_length = 0;
rabin_index[pos] = be->length;
ctx->blocks[pos].cksum_n_offset = be->offset;
ctx->blocks[pos]->cksum_n_offset = be->offset;
trans[blk] = pos;
pos++;
} else {
@ -618,7 +630,7 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
prev_index = 0;
prev_length = 0;
rabin_index[pos] = be->length;
ctx->blocks[pos].cksum_n_offset = be->offset;
ctx->blocks[pos]->cksum_n_offset = be->offset;
trans[blk] = pos;
pos++;
}
@ -627,8 +639,8 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
} else {
prev_index = 0;
prev_length = 0;
ctx->blocks[pos].cksum_n_offset = be->offset;
ctx->blocks[pos].mean_n_length = be->length;
ctx->blocks[pos]->cksum_n_offset = be->offset;
ctx->blocks[pos]->mean_n_length = be->length;
trans[blk] = pos;
if (be->similar == SIMILAR_EXACT) {
@ -662,22 +674,22 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
}
if (rabin_index[blk] & RABIN_INDEX_FLAG) {
j = rabin_index[blk] & RABIN_INDEX_VALUE;
i = ctx->blocks[j].index;
i = ctx->blocks[j]->index;
if (rabin_index[blk] & GET_SIMILARITY_FLAG) {
old = buf1 + ctx->blocks[j].offset;
new = buf1 + ctx->blocks[blk].cksum_n_offset;
old = buf1 + ctx->blocks[j]->offset;
new = buf1 + ctx->blocks[blk]->cksum_n_offset;
matchlen = ctx->real_chunksize - *size;
DEBUG_STAT_EN(delta_calls++);
bsz = bsdiff(old, ctx->blocks[j].length, new,
ctx->blocks[blk].mean_n_length, ctx->cbuf + pos1,
bsz = bsdiff(old, ctx->blocks[j]->length, new,
ctx->blocks[blk]->mean_n_length, ctx->cbuf + pos1,
buf1 + *size, matchlen);
if (bsz == 0) {
DEBUG_STAT_EN(delta_fails++);
memcpy(ctx->cbuf + pos1, new, ctx->blocks[blk].mean_n_length);
rabin_index[blk] = htonl(ctx->blocks[blk].mean_n_length);
pos1 += ctx->blocks[blk].mean_n_length;
memcpy(ctx->cbuf + pos1, new, ctx->blocks[blk]->mean_n_length);
rabin_index[blk] = htonl(ctx->blocks[blk]->mean_n_length);
pos1 += ctx->blocks[blk]->mean_n_length;
} else {
rabin_index[blk] = htonl(trans[i] |
RABIN_INDEX_FLAG | SET_SIMILARITY_FLAG);
@ -687,7 +699,7 @@ rabin_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size, ssize_t offset, s
rabin_index[blk] = htonl(trans[i] | RABIN_INDEX_FLAG);
}
} else {
memcpy(ctx->cbuf + pos1, buf1 + ctx->blocks[blk].cksum_n_offset,
memcpy(ctx->cbuf + pos1, buf1 + ctx->blocks[blk]->cksum_n_offset,
rabin_index[blk]);
pos1 += rabin_index[blk];
rabin_index[blk] = htonl(rabin_index[blk]);
@ -708,7 +720,6 @@ cont:
ctx->valid = 1;
DEBUG_STAT_EN(printf("Deduped size: %lld, blknum: %u, delta_calls: %u, delta_fails: %u\n",
*size, blknum, delta_calls, delta_fails));
/*
* Remaining header entries: size of compressed index and size of
* compressed data are inserted later via rabin_update_hdr, after actual compression!
@ -765,26 +776,28 @@ rabin_inverse_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size)
ctx->valid = 1;
for (blk = 0; blk < blknum; blk++) {
if (ctx->blocks[blk] == 0)
ctx->blocks[blk] = (rabin_blockentry_t *)slab_alloc(NULL, sizeof (rabin_blockentry_t));
len = ntohl(rabin_index[blk]);
if (len == 0) {
ctx->blocks[blk].length = 0;
ctx->blocks[blk].index = 0;
ctx->blocks[blk]->length = 0;
ctx->blocks[blk]->index = 0;
} else if (!(len & RABIN_INDEX_FLAG)) {
ctx->blocks[blk].length = len;
ctx->blocks[blk].offset = pos1;
ctx->blocks[blk]->length = len;
ctx->blocks[blk]->offset = pos1;
pos1 += len;
} else {
bsize_t blen;
ctx->blocks[blk].length = 0;
ctx->blocks[blk]->length = 0;
if (len & GET_SIMILARITY_FLAG) {
ctx->blocks[blk].offset = pos1;
ctx->blocks[blk].index = (len & RABIN_INDEX_VALUE) | SET_SIMILARITY_FLAG;
ctx->blocks[blk]->offset = pos1;
ctx->blocks[blk]->index = (len & RABIN_INDEX_VALUE) | SET_SIMILARITY_FLAG;
blen = get_bsdiff_sz(buf + pos1);
pos1 += blen;
} else {
ctx->blocks[blk].index = len & RABIN_INDEX_VALUE;
ctx->blocks[blk]->index = len & RABIN_INDEX_VALUE;
}
}
}
@ -793,19 +806,19 @@ rabin_inverse_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size)
int rv;
bsize_t newsz;
if (ctx->blocks[blk].length == 0 && ctx->blocks[blk].index == 0) continue;
if (ctx->blocks[blk].length > 0) {
len = ctx->blocks[blk].length;
pos1 = ctx->blocks[blk].offset;
if (ctx->blocks[blk]->length == 0 && ctx->blocks[blk]->index == 0) continue;
if (ctx->blocks[blk]->length > 0) {
len = ctx->blocks[blk]->length;
pos1 = ctx->blocks[blk]->offset;
} else {
oblk = ctx->blocks[blk].index;
oblk = ctx->blocks[blk]->index;
if (oblk & GET_SIMILARITY_FLAG) {
oblk = oblk & CLEAR_SIMILARITY_FLAG;
len = ctx->blocks[oblk].length;
pos1 = ctx->blocks[oblk].offset;
len = ctx->blocks[oblk]->length;
pos1 = ctx->blocks[oblk]->offset;
newsz = data_sz - sz;
rv = bspatch(buf + ctx->blocks[blk].offset, buf + pos1, len, pos2, &newsz);
rv = bspatch(buf + ctx->blocks[blk]->offset, buf + pos1, len, pos2, &newsz);
if (rv == 0) {
fprintf(stderr, "Failed to bspatch block.\n");
ctx->valid = 0;
@ -820,8 +833,8 @@ rabin_inverse_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size)
}
continue;
} else {
len = ctx->blocks[oblk].length;
pos1 = ctx->blocks[oblk].offset;
len = ctx->blocks[oblk]->length;
pos1 = ctx->blocks[oblk]->offset;
}
}
memcpy(pos2, buf + pos1, len);

View file

@ -142,6 +142,7 @@ typedef struct {
ssize_t offset;
uint64_t cksum_n_offset; // Dual purpose variable
uint64_t mean_n_length; // Dual purpose variable
uint64_t crc;
unsigned int index;
unsigned int length;
unsigned char ref, similar;
@ -149,7 +150,8 @@ typedef struct {
typedef struct {
unsigned char *current_window_data;
rabin_blockentry_t *blocks;
rabin_blockentry_t **blocks;
uint32_t blknum;
unsigned char *cbuf;
int window_pos;
uint32_t rabin_poly_max_block_size;

View file

@ -217,7 +217,7 @@ Read_Adjusted(int fd, uchar_t *buf, size_t count, ssize_t *rabin_count, void *ct
if (rcount > 0) {
rcount += *rabin_count;
if (rcount == count)
rabin_dedup(rctx, buf, &rcount, *rabin_count, rabin_count);
rabin_dedup(rctx, buf, &rcount, 0, rabin_count);
else
*rabin_count = 0;
} else {