1This patch adds the --detect-renamed option which makes rsync notice files 2that either (1) match in size & modify-time (plus the basename, if possible) 3or (2) match in size & checksum (when --checksum was also specified) and use 4each match as an alternate basis file to speed up the transfer. 5 6The algorithm attempts to scan the receiving-side's files in an efficient 7manner. If --delete[-before] is enabled, we'll take advantage of the 8pre-transfer delete pass to prepare any alternate-basis-file matches we 9might find. If --delete-before is not enabled, rsync does the rename scan 10during the regular file-sending scan (scanning each directory right before 11the generator starts updating files from that dir). In this latter mode, 12rsync might delay the updating of a file (if no alternate-basis match was 13yet found) until the full scan of the receiving side is complete, at which 14point any delayed files are processed. 15 16I chose to hard-link the alternate-basis files into a ".~tmp~" subdir that 17takes advantage of rsync's pre-existing partial-dir logic. This uses less 18memory than trying to keep track of the matches internally, and also allows 19any deletions or file-updates to occur normally without interfering with 20these alternate-basis discoveries. 21 22To use this patch, run these commands for a successful build: 23 24 patch -p1 <patches/detect-renamed.diff 25 ./configure (optional if already run) 26 make 27 28TODO: 29 30 We need to never return a match from fattr_find() that has a basis 31 file. This will ensure that we don't try to give a renamed file to 32 a file that can't use it, while missing out on giving it to a file 33 that could use it. 34 35--- old/flist.c 36+++ new/flist.c 37@@ -51,6 +51,7 @@ extern int implied_dirs; 38 extern int prune_empty_dirs; 39 extern int copy_links; 40 extern int copy_unsafe_links; 41+extern int detect_renamed; 42 extern int protocol_version; 43 extern int sanitize_paths; 44 extern struct stats stats; 45@@ -68,6 +69,8 @@ int checksum_len; 46 dev_t filesystem_dev; /* used to implement -x */ 47 unsigned int file_struct_len; 48 49+struct file_list the_fattr_list; 50+ 51 static char empty_sum[MD4_SUM_LENGTH]; 52 static int flist_count_offset; 53 54@@ -250,6 +253,44 @@ static mode_t from_wire_mode(int mode) 55 return mode; 56 } 57 58+static int fattr_compare(struct file_struct **file1, struct file_struct **file2) 59+{ 60+ struct file_struct *f1 = *file1; 61+ struct file_struct *f2 = *file2; 62+ int diff; 63+ 64+ if (!f1->basename || !S_ISREG(f1->mode) || !f1->length) { 65+ if (!f2->basename || !S_ISREG(f2->mode) || !f2->length) 66+ return 0; 67+ return 1; 68+ } 69+ if (!f2->basename || !S_ISREG(f2->mode) || !f2->length) 70+ return -1; 71+ 72+ /* Don't use diff for values that are longer than an int. */ 73+ if (f1->length != f2->length) 74+ return f1->length < f2->length ? -1 : 1; 75+ 76+ if (always_checksum) { 77+ diff = u_memcmp(f1->u.sum, f2->u.sum, checksum_len); 78+ if (diff) 79+ return diff; 80+ } else if (f1->modtime != f2->modtime) 81+ return f1->modtime < f2->modtime ? -1 : 1; 82+ 83+ diff = u_strcmp(f1->basename, f2->basename); 84+ if (diff) 85+ return diff; 86+ 87+ if (f1->dirname == f2->dirname) 88+ return 0; 89+ if (!f1->dirname) 90+ return -1; 91+ if (!f2->dirname) 92+ return 1; 93+ return u_strcmp(f1->dirname, f2->dirname); 94+} 95+ 96 static void send_directory(int f, struct file_list *flist, 97 char *fbuf, int len); 98 99@@ -1379,6 +1420,25 @@ struct file_list *recv_file_list(int f) 100 101 clean_flist(flist, relative_paths, 1); 102 103+ if (detect_renamed) { 104+ int j = flist->count; 105+ the_fattr_list.count = j; 106+ the_fattr_list.files = new_array(struct file_struct *, j); 107+ if (!the_fattr_list.files) 108+ goto oom; 109+ memcpy(the_fattr_list.files, flist->files, 110+ j * sizeof (struct file_struct *)); 111+ qsort(the_fattr_list.files, j, 112+ sizeof the_fattr_list.files[0], (int (*)())fattr_compare); 113+ the_fattr_list.low = 0; 114+ while (j-- > 0) { 115+ struct file_struct *fp = the_fattr_list.files[j]; 116+ if (fp->basename && S_ISREG(fp->mode) && fp->length) 117+ break; 118+ } 119+ the_fattr_list.high = j; 120+ } 121+ 122 if (f >= 0) { 123 recv_uid_list(f, flist); 124 125--- old/generator.c 126+++ new/generator.c 127@@ -76,6 +76,7 @@ extern char *basis_dir[]; 128 extern int compare_dest; 129 extern int copy_dest; 130 extern int link_dest; 131+extern int detect_renamed; 132 extern int whole_file; 133 extern int list_only; 134 extern int new_root_dir; 135@@ -91,12 +92,15 @@ extern char *backup_dir; 136 extern char *backup_suffix; 137 extern int backup_suffix_len; 138 extern struct file_list *the_file_list; 139+extern struct file_list the_fattr_list; 140 extern struct filter_list_struct server_filter_list; 141 142 static int deletion_count = 0; /* used to implement --max-delete */ 143+static int unexplored_dirs = 1; 144 145-/* For calling delete_file() */ 146+/* For calling delete_item() and delete_in_dir() */ 147 #define DEL_FORCE_RECURSE (1<<1) /* recurse even w/o --force */ 148+#define DEL_NO_DELETIONS (1<<2) 149 #define DEL_TERSE (1<<3) 150 151 152@@ -106,12 +110,120 @@ static int is_backup_file(char *fn) 153 return k > 0 && strcmp(fn+k, backup_suffix) == 0; 154 } 155 156+/* Search for a regular file that matches either (1) the size & modified 157+ * time (plus the basename, if possible) or (2) the size & checksum. If 158+ * we find an exact match down to the dirname, return -1 because we found 159+ * an up-to-date file in the transfer, not a renamed file. */ 160+static int fattr_find(struct file_struct *f, char *fname, alloc_pool_t pool) 161+{ 162+ int low = the_fattr_list.low, high = the_fattr_list.high; 163+ int mid, ok_match = -1, good_match = -1; 164+ struct file_struct *fmid; 165+ int diff; 166+ 167+ while (low <= high) { 168+ mid = (low + high) / 2; 169+ fmid = the_fattr_list.files[mid]; 170+ if (fmid->length != f->length) { 171+ if (fmid->length < f->length) 172+ low = mid + 1; 173+ else 174+ high = mid - 1; 175+ continue; 176+ } 177+ if (always_checksum) { 178+ if (!f->u.sum) { 179+ if (fmid->modtime == f->modtime 180+ && f_name_cmp(fmid, f) == 0) 181+ return -1; /* assume we can't help */ 182+ f->u.sum = pool_alloc(pool, MD4_SUM_LENGTH, 183+ "fattr_find"); 184+ file_checksum(fname, f->u.sum, f->length); 185+ } 186+ diff = u_memcmp(fmid->u.sum, f->u.sum, checksum_len); 187+ if (diff) { 188+ if (diff < 0) 189+ low = mid + 1; 190+ else 191+ high = mid - 1; 192+ continue; 193+ } 194+ } else { 195+ if (fmid->modtime != f->modtime) { 196+ if (fmid->modtime < f->modtime) 197+ low = mid + 1; 198+ else 199+ high = mid - 1; 200+ continue; 201+ } 202+ } 203+ ok_match = mid; 204+ diff = u_strcmp(fmid->basename, f->basename); 205+ if (diff == 0) { 206+ good_match = mid; 207+ if (fmid->dirname == f->dirname) 208+ return -1; /* file is up-to-date */ 209+ if (!fmid->dirname) { 210+ low = mid + 1; 211+ continue; 212+ } 213+ if (!f->dirname) { 214+ high = mid - 1; 215+ continue; 216+ } 217+ diff = u_strcmp(fmid->dirname, f->dirname); 218+ if (diff == 0) 219+ return -1; /* file is up-to-date */ 220+ } 221+ if (diff < 0) 222+ low = mid + 1; 223+ else 224+ high = mid - 1; 225+ } 226+ 227+ return good_match >= 0 ? good_match : ok_match; 228+} 229+ 230+static void look_for_rename(struct file_struct *file, char *fname, 231+ alloc_pool_t pool) 232+{ 233+ struct file_struct *fp; 234+ char *partialptr, *fn; 235+ STRUCT_STAT st; 236+ int ndx; 237+ 238+ if ((ndx = fattr_find(file, fname, pool)) < 0) 239+ return; 240+ 241+ fp = the_fattr_list.files[ndx]; 242+ fn = f_name(fp, NULL); 243+ /* We don't provide an alternate-basis file if there is a basis file. */ 244+ if (link_stat(fn, &st, 0) == 0) 245+ return; 246+ if ((partialptr = partial_dir_fname(fn)) == NULL 247+ || !handle_partial_dir(partialptr, PDIR_CREATE)) 248+ return; 249+ 250+ /* We only use the file if we can hard-link it into our tmp dir. */ 251+ if (link(fname, partialptr) == 0) { 252+ if (verbose > 2) { 253+ rprintf(FINFO, "found renamed: %s => %s\n", 254+ fname, partialptr); 255+ } 256+ return; 257+ } 258+ 259+ if (errno != EEXIST) 260+ handle_partial_dir(partialptr, PDIR_DELETE); 261+} 262 263 /* Delete a file or directory. If DEL_FORCE_RECURSE is set in the flags, or if 264 * force_delete is set, this will delete recursively. 265 * 266 * Note that fname must point to a MAXPATHLEN buffer if the mode indicates it's 267 * a directory! (The buffer is used for recursion, but returned unchanged.) 268+ * 269+ * Also Note: --detect-rename may use this routine with DEL_NO_DELETIONS set! 270 */ 271 static int delete_item(char *fname, int mode, int flags) 272 { 273@@ -122,6 +234,8 @@ static int delete_item(char *fname, int 274 char *p; 275 276 if (!S_ISDIR(mode)) { 277+ if (flags & DEL_NO_DELETIONS) 278+ return 0; 279 if (max_delete && ++deletion_count > max_delete) 280 return 0; 281 if (make_backups && (backup_dir || !is_backup_file(fname))) 282@@ -144,6 +258,7 @@ static int delete_item(char *fname, int 283 284 zap_dir = flags & DEL_FORCE_RECURSE || force_delete; 285 if ((max_delete && ++deletion_count > max_delete) 286+ || flags & DEL_NO_DELETIONS 287 || (dry_run && zap_dir)) { 288 ok = 0; 289 errno = ENOTEMPTY; 290@@ -186,6 +301,8 @@ static int delete_item(char *fname, int 291 continue; 292 293 strlcpy(p, fp->basename, remainder); 294+ if (detect_renamed && S_ISREG(fp->mode)) 295+ look_for_rename(fp, fname, dirlist->file_pool); 296 delete_item(fname, fp->mode, flags & ~DEL_TERSE); 297 } 298 flist_free(dirlist); 299@@ -194,7 +311,8 @@ static int delete_item(char *fname, int 300 301 pop_local_filters(save_filters); 302 303- if (max_delete && ++deletion_count > max_delete) 304+ if (flags & DEL_NO_DELETIONS 305+ || (max_delete && ++deletion_count > max_delete)) 306 return 0; 307 308 if (do_rmdir(fname) == 0) { 309@@ -214,15 +332,19 @@ static int delete_item(char *fname, int 310 * all the --delete-WHEN options. Note that the fbuf pointer must point to a 311 * MAXPATHLEN buffer with the name of the directory in it (the functions we 312 * call will append names onto the end, but the old dir value will be restored 313- * on exit). */ 314+ * on exit). 315+ * 316+ * Note: --detect-rename may use this routine with DEL_NO_DELETIONS set! 317+ */ 318 static void delete_in_dir(struct file_list *flist, char *fbuf, 319- struct file_struct *file, STRUCT_STAT *stp) 320+ struct file_struct *file, STRUCT_STAT *stp, int flags) 321 { 322 static int min_depth = MAXPATHLEN, cur_depth = -1; 323 static void *filt_array[MAXPATHLEN/2+1]; 324 static int already_warned = 0; 325 struct file_list *dirlist; 326- char delbuf[MAXPATHLEN]; 327+ char *p, delbuf[MAXPATHLEN]; 328+ unsigned remainder; 329 int dlen, i; 330 331 if (!flist) { 332@@ -236,6 +358,8 @@ static void delete_in_dir(struct file_li 333 if (verbose > 2) 334 rprintf(FINFO, "delete_in_dir(%s)\n", fbuf); 335 336+ flags |= DEL_FORCE_RECURSE; 337+ 338 if (allowed_lull) 339 maybe_send_keepalive(); 340 341@@ -243,12 +367,14 @@ static void delete_in_dir(struct file_li 342 return; /* Impossible... */ 343 344 if (io_error && !(lp_ignore_errors(module_id) || ignore_errors)) { 345- if (already_warned) 346+ if (!already_warned) { 347+ rprintf(FINFO, 348+ "IO error encountered -- skipping file deletion\n"); 349+ already_warned = 1; 350+ } 351+ if (!detect_renamed) 352 return; 353- rprintf(FINFO, 354- "IO error encountered -- skipping file deletion\n"); 355- already_warned = 1; 356- return; 357+ flags |= DEL_NO_DELETIONS; 358 } 359 360 while (cur_depth >= file->dir.depth && cur_depth >= min_depth) 361@@ -259,6 +385,9 @@ static void delete_in_dir(struct file_li 362 dlen = strlen(fbuf); 363 filt_array[cur_depth] = push_local_filters(fbuf, dlen); 364 365+ if (detect_renamed) 366+ unexplored_dirs--; 367+ 368 if (one_file_system) { 369 if (file->flags & FLAG_TOP_DIR) 370 filesystem_dev = stp->st_dev; 371@@ -268,18 +397,30 @@ static void delete_in_dir(struct file_li 372 373 dirlist = get_dirlist(fbuf, dlen, 0); 374 375+ p = fbuf + dlen; 376+ if (dlen != 1 || *fbuf != '/') 377+ *p++ = '/'; 378+ remainder = MAXPATHLEN - (p - fbuf); 379+ 380 /* If an item in dirlist is not found in flist, delete it 381 * from the filesystem. */ 382 for (i = dirlist->count; i--; ) { 383 struct file_struct *fp = dirlist->files[i]; 384 if (!fp->basename || fp->flags & FLAG_MOUNT_POINT) 385 continue; 386+ if (detect_renamed && S_ISREG(fp->mode)) { 387+ strlcpy(p, fp->basename, remainder); 388+ look_for_rename(fp, fbuf, dirlist->file_pool); 389+ } 390 if (flist_find(flist, fp) < 0) { 391 f_name(fp, delbuf); 392- delete_item(delbuf, fp->mode, DEL_FORCE_RECURSE); 393- } 394+ delete_item(delbuf, fp->mode, flags); 395+ } else if (detect_renamed && S_ISDIR(fp->mode)) 396+ unexplored_dirs++; 397 } 398 399+ fbuf[dlen] = '\0'; 400+ 401 flist_free(dirlist); 402 } 403 404@@ -309,9 +450,9 @@ static void do_delete_pass(struct file_l 405 || !S_ISDIR(st.st_mode)) 406 continue; 407 408- delete_in_dir(flist, fbuf, file, &st); 409+ delete_in_dir(flist, fbuf, file, &st, 0); 410 } 411- delete_in_dir(NULL, NULL, NULL, NULL); 412+ delete_in_dir(NULL, NULL, NULL, NULL, 0); 413 414 if (do_progress && !am_server) 415 rprintf(FINFO, " \r"); 416@@ -771,6 +912,7 @@ static int try_dests_non(struct file_str 417 return -1; 418 } 419 420+static struct bitbag *delayed_bits = NULL; 421 static int phase = 0; 422 423 /* Acts on the_file_list->file's ndx'th item, whose name is fname. If a dir, 424@@ -944,8 +1086,12 @@ static void recv_generator(char *fname, 425 && verbose && code != FNONE && f_out != -1) 426 rprintf(code, "%s/\n", fname); 427 if (delete_during && f_out != -1 && !phase && dry_run < 2 428- && (file->flags & FLAG_DEL_HERE)) 429- delete_in_dir(the_file_list, fname, file, &st); 430+ && (file->flags & FLAG_DEL_HERE)) { 431+ if (detect_renamed && statret != 0) 432+ unexplored_dirs++; 433+ delete_in_dir(the_file_list, fname, file, &st, 434+ delete_during < 0 ? DEL_NO_DELETIONS : 0); 435+ } 436 return; 437 } 438 439@@ -1201,8 +1347,14 @@ static void recv_generator(char *fname, 440 && hard_link_check(file, ndx, fname, statret, &st, 441 itemizing, code, HL_SKIP)) 442 return; 443- if (stat_errno == ENOENT) 444+ if (stat_errno == ENOENT) { 445+ if (detect_renamed && unexplored_dirs > 0 446+ && file->length) { 447+ bitbag_set_bit(delayed_bits, ndx); 448+ return; 449+ } 450 goto notify_others; 451+ } 452 rsyserr(FERROR, stat_errno, "recv_generator: failed to stat %s", 453 full_fname(fname)); 454 return; 455@@ -1388,11 +1540,17 @@ void generate_files(int f_out, struct fi 456 (long)getpid(), flist->count); 457 } 458 459+ if (detect_renamed) { 460+ delayed_bits = bitbag_create(flist->count); 461+ if (!delete_before && !delete_during) 462+ delete_during = -1; 463+ } 464+ 465 if (delete_before && !local_name && flist->count > 0) 466 do_delete_pass(flist); 467 do_progress = 0; 468 469- if (append_mode || whole_file < 0) 470+ if (append_mode || detect_renamed || whole_file < 0) 471 whole_file = 0; 472 if (verbose >= 2) { 473 rprintf(FINFO, "delta-transmission %s\n", 474@@ -1447,7 +1605,23 @@ void generate_files(int f_out, struct fi 475 } 476 recv_generator(NULL, NULL, 0, 0, 0, code, -1); 477 if (delete_during) 478- delete_in_dir(NULL, NULL, NULL, NULL); 479+ delete_in_dir(NULL, NULL, NULL, NULL, 0); 480+ 481+ if (detect_renamed) { 482+ if (delete_during < 0) 483+ delete_during = 0; 484+ detect_renamed = 0; 485+ 486+ for (i = -1; (i = bitbag_next_bit(delayed_bits, i)) >= 0; ) { 487+ struct file_struct *file = flist->files[i]; 488+ if (local_name) 489+ strlcpy(fbuf, local_name, sizeof fbuf); 490+ else 491+ f_name(file, fbuf); 492+ recv_generator(fbuf, file, i, itemizing, 493+ maybe_ATTRS_REPORT, code, f_out); 494+ } 495+ } 496 497 phase++; 498 csum_length = SUM_LENGTH; 499--- old/options.c 500+++ new/options.c 501@@ -78,6 +78,7 @@ int am_generator = 0; 502 int am_starting_up = 1; 503 int relative_paths = -1; 504 int implied_dirs = 1; 505+int detect_renamed = 0; 506 int numeric_ids = 0; 507 int allow_8bit_chars = 0; 508 int force_delete = 0; 509@@ -346,6 +347,7 @@ void usage(enum logcode F) 510 rprintf(F," --modify-window=NUM compare mod-times with reduced accuracy\n"); 511 rprintf(F," -T, --temp-dir=DIR create temporary files in directory DIR\n"); 512 rprintf(F," -y, --fuzzy find similar file for basis if no dest file\n"); 513+ rprintf(F," --detect-renamed try to find renamed files to speed up the transfer\n"); 514 rprintf(F," --compare-dest=DIR also compare destination files relative to DIR\n"); 515 rprintf(F," --copy-dest=DIR ... and include copies of unchanged files\n"); 516 rprintf(F," --link-dest=DIR hardlink to files in DIR when unchanged\n"); 517@@ -499,6 +501,7 @@ static struct poptOption long_options[] 518 {"compare-dest", 0, POPT_ARG_STRING, 0, OPT_COMPARE_DEST, 0, 0 }, 519 {"copy-dest", 0, POPT_ARG_STRING, 0, OPT_COPY_DEST, 0, 0 }, 520 {"link-dest", 0, POPT_ARG_STRING, 0, OPT_LINK_DEST, 0, 0 }, 521+ {"detect-renamed", 0, POPT_ARG_NONE, &detect_renamed, 0, 0, 0 }, 522 {"fuzzy", 'y', POPT_ARG_NONE, &fuzzy_basis, 0, 0, 0 }, 523 {"compress", 'z', POPT_ARG_NONE, 0, 'z', 0, 0 }, 524 {"compress-level", 0, POPT_ARG_INT, &def_compress_level, 'z', 0, 0 }, 525@@ -1362,7 +1365,7 @@ int parse_arguments(int *argc, const cha 526 inplace = 1; 527 } 528 529- if (delay_updates && !partial_dir) 530+ if ((delay_updates || detect_renamed) && !partial_dir) 531 partial_dir = tmp_partialdir; 532 533 if (inplace) { 534@@ -1371,6 +1374,7 @@ int parse_arguments(int *argc, const cha 535 snprintf(err_buf, sizeof err_buf, 536 "--%s cannot be used with --%s\n", 537 append_mode ? "append" : "inplace", 538+ detect_renamed ? "detect-renamed" : 539 delay_updates ? "delay-updates" : "partial-dir"); 540 return 0; 541 } 542@@ -1674,6 +1678,8 @@ void server_options(char **args,int *arg 543 args[ac++] = "--super"; 544 if (size_only) 545 args[ac++] = "--size-only"; 546+ if (detect_renamed) 547+ args[ac++] = "--detect-renamed"; 548 } 549 550 if (modify_window_set) { 551--- old/rsync.yo 552+++ new/rsync.yo 553@@ -363,6 +363,7 @@ to the detailed description below for a 554 --modify-window=NUM compare mod-times with reduced accuracy 555 -T, --temp-dir=DIR create temporary files in directory DIR 556 -y, --fuzzy find similar file for basis if no dest file 557+ --detect-renamed try to find renamed files to speed the xfer 558 --compare-dest=DIR also compare received files relative to DIR 559 --copy-dest=DIR ... and include copies of unchanged files 560 --link-dest=DIR hardlink to files in DIR when unchanged 561@@ -1259,6 +1260,15 @@ Note that the use of the bf(--delete) op 562 fuzzy-match files, so either use bf(--delete-after) or specify some 563 filename exclusions if you need to prevent this. 564 565+dit(bf(--detect-renamed)) This option tells rsync to scan the receiving 566+side for files that have been renamed, and to use any that are found as 567+alternate basis files to help speed up the transfer. 568+By default, alternate-basis files are hard-linked into a directory named 569+".~tmp~" in each file's destination directory, but if you've specified 570+the bf(--partial-dir) option, that directory will be used instead. These 571+potential alternate-basis files will be removed as the transfer progresses. 572+This option conflicts with bf(--inplace) and bf(--append). 573+ 574 dit(bf(--compare-dest=DIR)) This option instructs rsync to use em(DIR) on 575 the destination machine as an additional hierarchy to compare destination 576 files against doing transfers (if the files are missing in the destination 577--- old/util.c 578+++ new/util.c 579@@ -1025,6 +1025,32 @@ int handle_partial_dir(const char *fname 580 return 1; 581 } 582 583+/* We need to supply our own strcmp function for file list comparisons 584+ * to ensure that signed/unsigned usage is consistent between machines. */ 585+int u_strcmp(const char *p1, const char *p2) 586+{ 587+ for ( ; *p1; p1++, p2++) { 588+ if (*p1 != *p2) 589+ break; 590+ } 591+ 592+ return (int)*(uchar*)p1 - (int)*(uchar*)p2; 593+} 594+ 595+/* We need a memcmp function compares unsigned-byte values. */ 596+int u_memcmp(const void *p1, const void *p2, size_t len) 597+{ 598+ const uchar *u1 = p1; 599+ const uchar *u2 = p2; 600+ 601+ while (len--) { 602+ if (*u1 != *u2) 603+ return (int)*u1 - (int)*u2; 604+ } 605+ 606+ return 0; 607+} 608+ 609 /** 610 * Determine if a symlink points outside the current directory tree. 611 * This is considered "unsafe" because e.g. when mirroring somebody 612--- old/proto.h 613+++ new/proto.h 614@@ -304,6 +304,8 @@ int pop_dir(char *dir); 615 char *full_fname(const char *fn); 616 char *partial_dir_fname(const char *fname); 617 int handle_partial_dir(const char *fname, int create); 618+int u_strcmp(const char *p1, const char *p2); 619+int u_memcmp(const void *p1, const void *p2, size_t len); 620 int unsafe_symlink(const char *dest, const char *src); 621 char *human_num(int64 num); 622 char *human_dnum(double dnum, int decimal_digits); 623--- old/rsync.1 624+++ new/rsync.1 625@@ -429,6 +429,7 @@ to the detailed description below for a 626 \-\-modify\-window=NUM compare mod-times with reduced accuracy 627 \-T, \-\-temp\-dir=DIR create temporary files in directory DIR 628 \-y, \-\-fuzzy find similar file for basis if no dest file 629+ \-\-detect\-renamed try to find renamed files to speed the xfer 630 \-\-compare\-dest=DIR also compare received files relative to DIR 631 \-\-copy\-dest=DIR \&.\&.\&. and include copies of unchanged files 632 \-\-link\-dest=DIR hardlink to files in DIR when unchanged 633@@ -1458,6 +1459,16 @@ Note that the use of the \fB\-\-delete\f 634 fuzzy-match files, so either use \fB\-\-delete\-after\fP or specify some 635 filename exclusions if you need to prevent this\&. 636 .IP 637+.IP "\fB\-\-detect\-renamed\fP" 638+This option tells rsync to scan the receiving 639+side for files that have been renamed, and to use any that are found as 640+alternate basis files to help speed up the transfer\&. 641+By default, alternate-basis files are hard-linked into a directory named 642+"\&.~tmp~" in each file\&'s destination directory, but if you\&'ve specified 643+the \fB\-\-partial\-dir\fP option, that directory will be used instead\&. These 644+potential alternate-basis files will be removed as the transfer progresses\&. 645+This option conflicts with \fB\-\-inplace\fP and \fB\-\-append\fP\&. 646+.IP 647 .IP "\fB\-\-compare\-dest=DIR\fP" 648 This option instructs rsync to use \fIDIR\fP on 649 the destination machine as an additional hierarchy to compare destination 650