Got rid of some cruft.
[rsync/rsync-patches.git] / checksum-updating.diff
CommitLineData
213d4328
WD
1This builds on the sender optimization feature of the checksum4mirrors
2patch and adds the ability to create and/or updates the .rsyncsums files
3when --checksum-updating (or "checksum updating = true") is specified.
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4
5To use this patch, run these commands for a successful build:
6
213d4328 7 patch -p1 <patches/checksum4mirrors.diff
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8 patch -p1 <patches/checksum-updating.diff
9 ./configure (optional if already run)
10 make
11
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12--- old/clientserver.c
13+++ new/clientserver.c
cdcd2137 14@@ -37,6 +37,7 @@ extern int sanitize_paths;
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15 extern int filesfrom_fd;
16 extern int remote_protocol;
17 extern int protocol_version;
18+extern int checksum_updating;
19 extern int io_timeout;
20 extern int no_detach;
21 extern int default_af_hint;
213d4328 22@@ -687,6 +688,8 @@ static int rsync_module(int f_in, int f_
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23 else if (am_root < 0) /* Treat --fake-super from client as --super. */
24 am_root = 2;
25
26+ checksum_updating = lp_checksum_updating(i);
27+
28 if (filesfrom_fd == 0)
29 filesfrom_fd = f_in;
30
31--- old/flist.c
32+++ new/flist.c
7e420a3e 33@@ -26,6 +26,7 @@
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34 #include "io.h"
35
36 extern int verbose;
37+extern int dry_run;
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38 extern int am_root;
39 extern int am_server;
cdcd2137
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40 extern int am_daemon;
41@@ -58,6 +59,7 @@ extern int implied_dirs;
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42 extern int file_extra_cnt;
43 extern int ignore_perishable;
44 extern int non_perishable_cnt;
45+extern int checksum_updating;
46 extern int prune_empty_dirs;
47 extern int copy_links;
48 extern int copy_unsafe_links;
cdcd2137 49@@ -82,6 +84,9 @@ extern iconv_t ic_send, ic_recv;
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50
51 #define PTR_SIZE (sizeof (struct file_struct *))
52
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53+#define FLAG_SUM_MISSING (1<<1) /* F_SUM() data is undefined */
54+#define FLAG_SUM_KEEP (1<<2) /* keep entry when rewriting */
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55+
56 int io_error;
57 int checksum_len;
58 dev_t filesystem_dev; /* used to implement -x */
213d4328 59@@ -117,6 +122,9 @@ static char empty_sum[MAX_DIGEST_LEN];
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60 static int flist_count_offset; /* for --delete --progress */
61 static int dir_count = 0;
505968ea 62 static int high_hlink_ndx;
ae10e51e 63+static int checksum_matches = 0;
071bf6df 64+static int checksum_updates = 0;
7200c744 65+static int regular_skipped = 0;
213d4328 66 static struct file_list *checksum_flist = NULL;
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67
68 static void clean_flist(struct file_list *flist, int strip_root);
213d4328 69@@ -307,7 +315,8 @@ static void flist_done_allocating(struct
ae10e51e 70
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71 /* The len count is the length of the basename + 1 for the null. */
72 static int add_checksum(const char *dirname, const char *basename, int len,
73- OFF_T file_length, time_t mtime, const char *sum)
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74+ OFF_T file_length, time_t mtime, int32 ctime, int32 inode,
75+ const char *sum, const char *alt_sum, int flags)
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76 {
77 struct file_struct *file;
78 int alloc_len, extra_len;
79@@ -318,13 +327,14 @@ static int add_checksum(const char *dirn
80 if (file_length == 0)
81 return 0;
82
83- extra_len = (file_extra_cnt + (file_length > 0xFFFFFFFFu) + SUM_EXTRA_CNT)
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84+ /* "2" is for a 32-bit ctime num and an 32-bit inode num. */
85+ extra_len = (file_extra_cnt + (file_length > 0xFFFFFFFFu) + SUM_EXTRA_CNT + 2)
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86 * EXTRA_LEN;
87 #if EXTRA_ROUNDING > 0
88 if (extra_len & (EXTRA_ROUNDING * EXTRA_LEN))
89 extra_len = (extra_len | (EXTRA_ROUNDING * EXTRA_LEN)) + EXTRA_LEN;
90 #endif
91- alloc_len = FILE_STRUCT_LEN + extra_len + len;
56522462 92+ alloc_len = FILE_STRUCT_LEN + extra_len + len + checksum_len*2 + 1;
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93 bp = pool_alloc(checksum_flist->file_pool, alloc_len, "add_checksum");
94
95 memset(bp, 0, extra_len + FILE_STRUCT_LEN);
96@@ -333,7 +343,14 @@ static int add_checksum(const char *dirn
97 bp += FILE_STRUCT_LEN;
98
99 memcpy(bp, basename, len);
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100+ if (alt_sum)
101+ strlcpy(bp+len, alt_sum, checksum_len*2 + 1);
102+ else {
103+ memset(bp+len, '=', checksum_len*2);
104+ bp[len+checksum_len*2] = '\0';
105+ }
213d4328 106
ae10e51e 107+ file->flags = flags;
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108 file->mode = S_IFREG;
109 file->modtime = mtime;
110 file->len32 = (uint32)file_length;
111@@ -344,6 +361,8 @@ static int add_checksum(const char *dirn
112 file->dirname = dirname;
113 bp = F_SUM(file);
114 memcpy(bp, sum, checksum_len);
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115+ F_CTIME(file) = ctime;
116+ F_INODE(file) = inode;
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117
118 flist_expand(checksum_flist, 1);
119 checksum_flist->files[checksum_flist->used++] = file;
120@@ -353,17 +372,104 @@ static int add_checksum(const char *dirn
121 return 1;
122 }
123
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124+static void write_checksums(const char *next_dirname, int whole_dir)
125+{
126+ static const char *dirname_save;
127+ char fbuf[MAXPATHLEN];
128+ const char *dirname;
e2bccb59 129+ int used, new_entries, counts_match, no_skipped;
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130+ FILE *out_fp;
131+ int i;
132+
133+ dirname = dirname_save;
134+ dirname_save = next_dirname;
135+
136+ if (!dirname)
137+ return;
138+
e2bccb59 139+ used = checksum_flist->used;
071bf6df 140+ new_entries = checksum_updates != 0;
e2bccb59 141+ counts_match = used == checksum_matches;
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142+ no_skipped = whole_dir && regular_skipped == 0;
143+
144+ clean_flist(checksum_flist, 0);
145+
e2bccb59 146+ checksum_flist->used = 0;
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147+ checksum_matches = 0;
148+ checksum_updates = 0;
149+ regular_skipped = 0;
150+
151+ if (dry_run)
152+ return;
153+
154+ if (*dirname) {
155+ if (pathjoin(fbuf, sizeof fbuf, dirname, ".rsyncsums") >= sizeof fbuf)
156+ return;
157+ } else
158+ strlcpy(fbuf, ".rsyncsums", sizeof fbuf);
159+
160+ if (checksum_flist->high - checksum_flist->low < 0 && no_skipped) {
161+ unlink(fbuf);
162+ return;
163+ }
164+
165+ if (!new_entries && (counts_match || !whole_dir))
166+ return;
167+
168+ if (!(out_fp = fopen(fbuf, "w")))
169+ return;
170+
171+ new_entries = 0;
172+ for (i = checksum_flist->low; i <= checksum_flist->high; i++) {
173+ struct file_struct *file = checksum_flist->sorted[i];
174+ const char *cp = F_SUM(file);
175+ const char *end = cp + checksum_len;
176+ const char *alt_sum = file->basename + strlen(file->basename) + 1;
e2bccb59 177+ int32 ctime, inode;
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178+ if (whole_dir && !(file->flags & FLAG_SUM_KEEP))
179+ continue;
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180+ ctime = F_CTIME(file);
181+ inode = F_INODE(file);
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182+ if (protocol_version >= 30)
183+ fprintf(out_fp, "%s ", alt_sum);
184+ if (file->flags & FLAG_SUM_MISSING) {
185+ new_entries++;
186+ do {
187+ fprintf(out_fp, "==");
188+ } while (++cp != end);
189+ } else {
190+ do {
505968ea 191+ fprintf(out_fp, "%02x", (int)CVAL(cp, 0));
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192+ } while (++cp != end);
193+ }
194+ if (protocol_version < 30)
195+ fprintf(out_fp, " %s", alt_sum);
196+ if (*alt_sum == '=')
197+ new_entries++;
e2bccb59 198+ fprintf(out_fp, " %10.0f %10.0f %10lu %10lu %s\n",
071bf6df 199+ (double)F_LENGTH(file), (double)file->modtime,
e2bccb59 200+ (long)ctime, (long)inode, file->basename);
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201+ }
202+
203+ fclose(out_fp);
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204+}
205+
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206 /* The direname value must remain unchanged during the lifespan of the
207 * created checksum_flist object because we use it directly. */
208 static void read_checksums(const char *dirname)
209 {
210 char line[MAXPATHLEN+1024], fbuf[MAXPATHLEN], sum[MAX_DIGEST_LEN];
56522462 211+ const char *alt_sum = NULL;
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212 OFF_T file_length;
213 time_t mtime;
214- int len, dlen, i;
e2bccb59 215+ int32 ctime, inode;
ae10e51e 216+ int len, dlen, i, flags;
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217 char *cp;
218 FILE *fp;
219
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220+ if (checksum_updating)
221+ write_checksums(dirname, 0);
071bf6df 222+
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223 if (checksum_flist) {
224 /* Reset the pool memory and empty the file-list array. */
225 pool_free_old(checksum_flist->file_pool,
226@@ -374,6 +480,9 @@ static void read_checksums(const char *d
227
228 checksum_flist->low = 0;
229 checksum_flist->high = -1;
ae10e51e 230+ checksum_matches = 0;
071bf6df 231+ checksum_updates = 0;
7200c744 232+ regular_skipped = 0;
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233
234 if (!dirname)
235 return;
236@@ -392,7 +501,7 @@ static void read_checksums(const char *d
237 while (fgets(line, sizeof line, fp)) {
238 cp = line;
239 if (protocol_version >= 30) {
240- char *alt_sum = cp;
56522462 241+ alt_sum = cp;
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242 if (*cp == '=')
243 while (*++cp == '=') {}
244 else
245@@ -403,7 +512,14 @@ static void read_checksums(const char *d
246 }
247
248 if (*cp == '=') {
249- continue;
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250+ for (i = 0; i < checksum_len*2; i++, cp++) {
251+ if (*cp != '=') {
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252+ cp = "";
253+ break;
254+ }
ae10e51e 255+ }
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256+ memset(sum, 0, checksum_len);
257+ flags = FLAG_SUM_MISSING;
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258 } else {
259 for (i = 0; i < checksum_len*2; i++, cp++) {
260 int x;
261@@ -421,13 +537,14 @@ static void read_checksums(const char *d
262 else
263 sum[i/2] = x << 4;
264 }
56522462 265+ flags = 0;
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266 }
267 if (*cp != ' ')
268 break;
269 while (*++cp == ' ') {}
270
271 if (protocol_version < 30) {
272- char *alt_sum = cp;
56522462 273+ alt_sum = cp;
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274 if (*cp == '=')
275 while (*++cp == '=') {}
276 else
277@@ -451,16 +568,16 @@ static void read_checksums(const char *d
278 break;
279 while (*++cp == ' ') {}
280
281- /* Ignore ctime. */
7200c744 282+ ctime = 0;
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283 while (isDigit(cp))
284- cp++;
7200c744 285+ ctime = ctime * 10 + *cp++ - '0';
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286 if (*cp != ' ')
287 break;
288 while (*++cp == ' ') {}
289
290- /* Ignore inode. */
e2bccb59 291+ inode = 0;
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292 while (isDigit(cp))
293- cp++;
e2bccb59 294+ inode = inode * 10 + *cp++ - '0';
213d4328
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295 if (*cp != ' ')
296 break;
297 while (*++cp == ' ') {}
298@@ -477,8 +594,13 @@ static void read_checksums(const char *d
299 continue;
300
301 strlcpy(fbuf+dlen, cp, sizeof fbuf - dlen);
ae10e51e 302+ if (is_excluded(fbuf, 0, ALL_FILTERS)) {
edf38a9d 303+ flags |= FLAG_SUM_KEEP;
ae10e51e 304+ checksum_matches++;
56522462 305+ }
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306
307- add_checksum(dirname, cp, len, file_length, mtime, sum);
e2bccb59 308+ add_checksum(dirname, cp, len, file_length, mtime, ctime, inode,
56522462 309+ sum, alt_sum, flags);
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310 }
311 fclose(fp);
312
313@@ -1260,6 +1382,8 @@ struct file_struct *make_file(const char
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314 if (is_excluded(thisname, S_ISDIR(st.st_mode) != 0, filter_level)) {
315 if (ignore_perishable)
316 non_perishable_cnt++;
317+ if (S_ISREG(st.st_mode))
318+ regular_skipped++;
319 return NULL;
320 }
321
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322@@ -1391,13 +1515,36 @@ struct file_struct *make_file(const char
323 int j;
324 if (flist && (j = flist_find(checksum_flist, file)) >= 0) {
325 struct file_struct *fp = checksum_flist->sorted[j];
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326+ int32 ctime = F_CTIME(fp);
327+ int32 inode = F_INODE(fp);
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328 if (F_LENGTH(fp) == st.st_size
329- && fp->modtime == st.st_mtime)
330- memcpy(tmp_sum, F_SUM(fp), MAX_DIGEST_LEN);
331- else
332- file_checksum(thisname, tmp_sum, st.st_size);
333- } else
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334+ && fp->modtime == st.st_mtime
335+ && ctime == (int32)st.st_ctime
336+ && inode == (int32)st.st_ino) {
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337+ if (fp->flags & FLAG_SUM_MISSING) {
338+ fp->flags &= ~FLAG_SUM_MISSING;
e2bccb59 339+ checksum_updates++;
56522462 340+ file_checksum(thisname, tmp_sum, st.st_size);
a3ba6627 341+ memcpy(F_SUM(fp), tmp_sum, MAX_DIGEST_LEN);
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342+ } else {
343+ checksum_matches++;
344+ memcpy(tmp_sum, F_SUM(fp), MAX_DIGEST_LEN);
345+ }
edf38a9d 346+ fp->flags |= FLAG_SUM_KEEP;
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347+ } else {
348+ clear_file(fp);
edf38a9d 349+ goto compute_new_checksum;
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350+ }
351+ } else {
edf38a9d 352+ compute_new_checksum:
213d4328 353 file_checksum(thisname, tmp_sum, st.st_size);
ae10e51e 354+ if (checksum_updating && flist) {
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355+ checksum_updates +=
356+ add_checksum(file->dirname, basename, basename_len,
357+ st.st_size, st.st_mtime, st.st_ctime,
358+ st.st_ino, tmp_sum, NULL, FLAG_SUM_KEEP);
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359+ }
360+ }
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361 }
362
ae10e51e 363 /* This code is only used by the receiver when it is building
213d4328 364@@ -1688,6 +1835,9 @@ static void send_directory(int f, struct
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365
366 closedir(d);
367
368+ if (checksum_updating && always_checksum && am_sender && f >= 0)
071bf6df 369+ write_checksums(NULL, 1);
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370+
371 if (f >= 0 && recurse && !divert_dirs) {
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372 int i, end = flist->used - 1;
373 /* send_if_directory() bumps flist->used, so use "end". */
213d4328 374@@ -2249,7 +2399,11 @@ struct file_list *send_file_list(int f,
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375 * file-list to check if this is a 1-file xfer. */
376 send_extra_file_list(f, 1);
377 }
378- }
379+ } else
380+ flist_eof = 1;
381+
382+ if (checksum_updating && always_checksum && flist_eof)
383+ read_checksums(NULL); /* writes any last updates */
384
385 return flist;
386 }
213d4328 387@@ -2535,7 +2689,7 @@ void flist_free(struct file_list *flist)
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388
389 if (!flist->prev || !flist_cnt)
390 pool_destroy(flist->file_pool);
391- else
392+ else if (flist->pool_boundary)
393 pool_free_old(flist->file_pool, flist->pool_boundary);
394
395 if (flist->sorted && flist->sorted != flist->files)
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396--- old/loadparm.c
397+++ new/loadparm.c
7e420a3e 398@@ -153,6 +153,7 @@ typedef struct
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399 int syslog_facility;
400 int timeout;
401
402+ BOOL checksum_updating;
403 BOOL fake_super;
404 BOOL ignore_errors;
405 BOOL ignore_nonreadable;
7e420a3e 406@@ -201,6 +202,7 @@ static service sDefault =
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407 /* syslog_facility; */ LOG_DAEMON,
408 /* timeout; */ 0,
409
410+ /* checksum_updating; */ False,
411 /* fake_super; */ False,
412 /* ignore_errors; */ False,
413 /* ignore_nonreadable; */ False,
7e420a3e 414@@ -317,6 +319,7 @@ static struct parm_struct parm_table[] =
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415 {"lock file", P_STRING, P_LOCAL, &sDefault.lock_file, NULL,0},
416 {"log file", P_STRING, P_LOCAL, &sDefault.log_file, NULL,0},
417 {"log format", P_STRING, P_LOCAL, &sDefault.log_format, NULL,0},
418+ {"checksum updating", P_BOOL, P_LOCAL, &sDefault.checksum_updating, NULL,0},
419 {"max connections", P_INTEGER,P_LOCAL, &sDefault.max_connections, NULL,0},
420 {"max verbosity", P_INTEGER,P_LOCAL, &sDefault.max_verbosity, NULL,0},
421 {"name", P_STRING, P_LOCAL, &sDefault.name, NULL,0},
7e420a3e 422@@ -422,6 +425,7 @@ FN_LOCAL_BOOL(lp_fake_super, fake_super)
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423 FN_LOCAL_BOOL(lp_ignore_errors, ignore_errors)
424 FN_LOCAL_BOOL(lp_ignore_nonreadable, ignore_nonreadable)
425 FN_LOCAL_BOOL(lp_list, list)
426+FN_LOCAL_BOOL(lp_checksum_updating, checksum_updating)
427 FN_LOCAL_BOOL(lp_read_only, read_only)
428 FN_LOCAL_BOOL(lp_strict_modes, strict_modes)
429 FN_LOCAL_BOOL(lp_transfer_logging, transfer_logging)
430--- old/options.c
431+++ new/options.c
7e420a3e 432@@ -110,6 +110,7 @@ size_t bwlimit_writemax = 0;
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433 int ignore_existing = 0;
434 int ignore_non_existing = 0;
435 int need_messages_from_generator = 0;
436+int checksum_updating = 0;
99650e0d 437 int max_delete = INT_MIN;
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438 OFF_T max_size = 0;
439 OFF_T min_size = 0;
7e420a3e 440@@ -310,6 +311,7 @@ void usage(enum logcode F)
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441 rprintf(F," -q, --quiet suppress non-error messages\n");
442 rprintf(F," --no-motd suppress daemon-mode MOTD (see manpage caveat)\n");
443 rprintf(F," -c, --checksum skip based on checksum, not mod-time & size\n");
56522462 444+ rprintf(F," --checksum-updating sender updates .rsyncsums files\n");
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445 rprintf(F," -a, --archive archive mode; equals -rlptgoD (no -H,-A,-X)\n");
446 rprintf(F," --no-OPTION turn off an implied OPTION (e.g. --no-D)\n");
447 rprintf(F," -r, --recursive recurse into directories\n");
505968ea 448@@ -557,6 +559,7 @@ static struct poptOption long_options[]
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449 {"checksum", 'c', POPT_ARG_VAL, &always_checksum, 1, 0, 0 },
450 {"no-checksum", 0, POPT_ARG_VAL, &always_checksum, 0, 0, 0 },
451 {"no-c", 0, POPT_ARG_VAL, &always_checksum, 0, 0, 0 },
452+ {"checksum-updating",0, POPT_ARG_NONE, &checksum_updating, 0, 0, 0 },
453 {"block-size", 'B', POPT_ARG_LONG, &block_size, 0, 0, 0 },
454 {"compare-dest", 0, POPT_ARG_STRING, 0, OPT_COMPARE_DEST, 0, 0 },
455 {"copy-dest", 0, POPT_ARG_STRING, 0, OPT_COPY_DEST, 0, 0 },
213d4328 456@@ -1954,7 +1957,9 @@ void server_options(char **args, int *ar
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457 args[ac++] = basis_dir[i];
458 }
459 }
460- }
461+ } else if (checksum_updating)
462+ args[ac++] = "--checksum-updating";
463+
464
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465 if (append_mode) {
466 if (append_mode > 1)
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467--- old/rsync.h
468+++ new/rsync.h
213d4328 469@@ -662,6 +662,10 @@ extern int xattrs_ndx;
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470 #define F_SUM(f) ((char*)OPT_EXTRA(f, LEN64_BUMP(f) + HLINK_BUMP(f) \
471 + SUM_EXTRA_CNT - 1))
7200c744 472
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473+/* These are only valid on an entry read from a checksum file. */
474+#define F_CTIME(f) OPT_EXTRA(f, LEN64_BUMP(f) + SUM_EXTRA_CNT)->num
475+#define F_INODE(f) OPT_EXTRA(f, LEN64_BUMP(f) + SUM_EXTRA_CNT + 1)->num
476+
477 /* Some utility defines: */
478 #define F_IS_ACTIVE(f) (f)->basename[0]
479 #define F_IS_HLINKED(f) ((f)->flags & FLAG_HLINKED)
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480--- old/rsync.yo
481+++ new/rsync.yo
213d4328 482@@ -317,6 +317,7 @@ to the detailed description below for a
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483 -q, --quiet suppress non-error messages
484 --no-motd suppress daemon-mode MOTD (see caveat)
485 -c, --checksum skip based on checksum, not mod-time & size
56522462 486+ --checksum-updating sender updates .rsyncsums files
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487 -a, --archive archive mode; equals -rlptgoD (no -H,-A,-X)
488 --no-OPTION turn off an implied OPTION (e.g. --no-D)
489 -r, --recursive recurse into directories
213d4328 490@@ -515,9 +516,9 @@ uses a "quick check" that (by default) c
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WD
491 of last modification match between the sender and receiver. This option
492 changes this to compare a 128-bit MD4 checksum for each file that has a
493 matching size. Generating the checksums means that both sides will expend
494-a lot of disk I/O reading all the data in the files in the transfer (and
495-this is prior to any reading that will be done to transfer changed files),
496-so this can slow things down significantly.
497+a lot of disk I/O reading the data in all the files in the transfer, so
498+this can slow things down significantly (and this is prior to any reading
499+that will be done to transfer the files that have changed).
500
501 The sending side generates its checksums while it is doing the file-system
502 scan that builds the list of the available files. The receiver generates
213d4328 503@@ -525,12 +526,42 @@ its checksums when it is scanning for ch
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504 file that has the same size as the corresponding sender's file: files with
505 either a changed size or a changed checksum are selected for transfer.
506
507+Starting with version 3.0.0, the sending side will look for a checksum
508+summary file and use a pre-generated checksum that it reads out of the file
509+(as long as it matches the file's size and modified time). This allows a
510+server to support the --checksum option to clients without having to
511+recompute the checksums for each client. See the bf(--checksum-updating)
56522462 512+option for a way to have rsync create/update these checksum files.
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513+
514 Note that rsync always verifies that each em(transferred) file was
515 correctly reconstructed on the receiving side by checking a whole-file
516 checksum that is generated when as the file is transferred, but that
517 automatic after-the-transfer verification has nothing to do with this
518 option's before-the-transfer "Does this file need to be updated?" check.
519
520+dit(bf(--checksum-updating)) This option tells the sending side to create
521+and/or update per-directory checksum files that are used by the
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522+bf(--checksum) option. The file that is updated is named .rsyncsums. If
523+pre-transfer checksums are not being computed, this option has no effect.
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524+
525+The checksum files stores the computed checksum, last-known size,
526+modification time, and name for each file in the current directory. If a
527+later transfer finds that a file matches its prior size and modification
528+time, the checksum is assumed to still be correct. Otherwise it is
529+recomputed and udpated in the file.
530+
531+To avoid transferring the system's checksum files, you can use an exclude
56522462 532+(e.g. bf(--exclude=.rsyncsums)). To make this easier to type, you can use
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533+a popt alias. For instance, adding the following line in your ~/.popt file
534+defines a bf(-cc) option that enables checksum updating and excludes the
535+checksum files:
536+
56522462 537+verb( rsync alias --cc --checksum-updating --exclude=.rsyncsums)
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538+
539+An rsync daemon does not allow the client to control this setting, so see
540+the "checksum updating" daemon config option for information on how to make
541+a daemon maintain these checksum files.
542+
543 dit(bf(-a, --archive)) This is equivalent to bf(-rlptgoD). It is a quick
544 way of saying you want recursion and want to preserve almost
545 everything (with -H being a notable omission).
546--- old/rsyncd.conf.yo
547+++ new/rsyncd.conf.yo
213d4328 548@@ -200,6 +200,20 @@ locking on this file to ensure that the
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549 exceeded for the modules sharing the lock file.
550 The default is tt(/var/run/rsyncd.lock).
551
552+dit(bf(checksum updating)) This option tells rsync to update/create the
553+checksum information in the per-directory checksum files when users copy
554+files using the bf(--checksum) option. Any file that has changed since it
555+was last checksummed (or is not mentioned) has its data updated in the
56522462 556+.rsyncsums file.
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557+
558+Note that this updating will occur even if the module is listed as being
559+read-only. If you want to hide these files (and you will almost always
56522462 560+want to do), add ".rsyncsums" to the module's exclude setting.
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561+
562+Note also that the client's command-line option, bf(--checksum-updating),
563+has no effect on a daemon. A daemon will only update/create checksum files
564+if this config option is true.
565+
566 dit(bf(read only)) The "read only" option determines whether clients
567 will be able to upload files or not. If "read only" is true then any
568 attempted uploads will fail. If "read only" is false then uploads will