Hello,
Mac OS X 10.9 has the bad habit of considering a rename on an UDF FS as
a file change; that is:
touch -t 201010101010 test
ls -l test
-rw-r--r-- 1 gui staff 0 10 oct 2010 test
mv test fail
ls -l fail
-rw-r--r-- 1 gui staff 0 29 nov 00:19 fail
rsync.c (3.1.2), in archive mode, calls set_file_attrs *before*
renaming .file.XXXXXX to file. So, in the aforementioned case, all times
beautifully crafted on the file get lost.
I would be glad to know if other OSes / FS combinations get such a
disturbing implementation.
Could this behavior be ground to an rsync enhancement request?
In this case, the attached POC code (well, a bit more than a POC,
because it is currently handling a 600 GB "rsync -a" to an UDF disk)
could serve as a base for an implementation.
It relies on the first temp file rename to detect bad behavior from the
FS, and if so, all subsequent set_file_attrs get delayed to after the
rename.
Everyone have a nice day!
--
Guillaume
--- rsync.c 2016-11-28 14:42:50.000000000 +0100
+++ rsync.c 2016-11-28 15:15:20.000000000 +0100
@@ -54,6 +54,9 @@
#ifdef ICONV_OPTION
extern char *iconv_opt;
#endif
+/* Do we modtime after or before renaming the temp file?
+ * 0: not decided yet; -1: modtime before rename; 1: after rename. */
+static int modtime_after_rename = 0;
#ifdef ICONV_CONST
iconv_t ic_chck = (iconv_t)-1;
@@ -636,6 +637,31 @@
exit_cleanup(RERR_SIGNAL);
}
+int maybe_set_file_attrs(int after_rename, const char *fname, struct file_struct *file,
+ stat_x *sxp, const char *fnamecmp, int ok_to_set_time)
+{
+ /* If we do not know yet what to do, and have a file to detect on, choose now. */
+ if (after_rename && modtime_after_rename == 0) {
+ stat_x stat_after_rename;
+ if (link_stat(fname, &stat_after_rename.st, 0) < 0)
+ /* Unable to read our just-created file; give up and keep the conservative
+ * value for modtime_after_rename. */
+ modtime_after_rename = -1;
+ else
+ modtime_after_rename = stat_after_rename.st.st_mtime == file->modtime ? -1 : 1;
+ }
+
+ if (
+ (after_rename && modtime_after_rename >= 0)
+ || (!after_rename && modtime_after_rename <= 0)
+ ) {
+ return set_file_attrs(fname, file, sxp, fnamecmp,
+ ok_to_set_time ? 0 : ATTRS_SKIP_MTIME);
+ }
+
+ return 1;
+}
+
/* Finish off a file transfer: renaming the file and setting the file's
* attributes (e.g. permissions, ownership, etc.). If the robust_rename()
* call is forced to copy the temp file and partialptr is both non-NULL and
@@ -665,8 +691,7 @@
}
/* Change permissions before putting the file into place. */
- set_file_attrs(fnametmp, file, NULL, fnamecmp,
- ok_to_set_time ? 0 : ATTRS_SKIP_MTIME);
+ maybe_set_file_attrs(0, fnametmp, file, NULL, fnamecmp, ok_to_set_time);
/* move tmp file over real file */
if (DEBUG_GTE(RECV, 1))
@@ -683,6 +708,7 @@
}
if (ret == 0) {
/* The file was moved into place (not copied), so it's done. */
+ maybe_set_file_attrs(1, fname, file, NULL, fnamecmp, ok_to_set_time);
return 1;
}
/* The file was copied, so tweak the perms of the copied file. If it
@@ -690,8 +716,7 @@
fnametmp = temp_copy_name ? temp_copy_name : fname;
do_set_file_attrs:
- set_file_attrs(fnametmp, file, NULL, fnamecmp,
- ok_to_set_time ? 0 : ATTRS_SKIP_MTIME);
+ maybe_set_file_attrs(0, fnametmp, file, NULL, fnamecmp, ok_to_set_time);
if (temp_copy_name) {
if (do_rename(fnametmp, fname) < 0) {
@@ -699,6 +724,7 @@
full_fname(fnametmp), fname);
return 0;
}
+ maybe_set_file_attrs(1, fname, file, NULL, fnamecmp, ok_to_set_time);
handle_partial_dir(temp_copy_name, PDIR_DELETE);
}
return 1;
--
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