Merge lp:~akopytov/percona-xtrabackup/bug925441 into lp:percona-xtrabackup/2.0

[Alexey Kopytov]

  The problem was that posix_fadvise(POSIX_FADV_DONTNEED) was used
  incorrectly, because the call just releases already cached pages from
  the pagecache, thus making a single-shot call before file access
  useless.

  Fixed by making sure the call is invoked after each read/write to
  make the feature work as advertised.

[Alexey Kopytov (akopytov)]

http://jenkins.percona.com/view/Percona%20Xtrabackup/job/percona-xtrabackup-param/164/

[Stewart Smith (stewart)]

review: Approve

=== modified file 'src/xtrabackup.c'
--- src/xtrabackup.c	2012-02-20 04:38:44 +0000
+++ src/xtrabackup.c	2012-03-22 11:21:18 +0000
@@ -3125,7 +3125,6 @@
 
 #ifdef USE_POSIX_FADVISE
 	posix_fadvise(src_file, 0, 0, POSIX_FADV_SEQUENTIAL);
-	posix_fadvise(src_file, 0, 0, POSIX_FADV_DONTNEED);
 #endif
 
 	if (my_stat(node->name, &src_stat, MYF(MY_WME)) == NULL) {
@@ -3188,6 +3187,10 @@
 			goto error;
 		}
 
+#ifdef USE_POSIX_FADVISE
+		posix_fadvise(src_file, 0, 0, POSIX_FADV_DONTNEED);
+#endif
+
 		/* check corruption and retry */
 		for (chunk_offset = 0; chunk_offset < chunk; chunk_offset += page_size) {
 #ifndef INNODB_VERSION_SHORT
@@ -3538,6 +3541,12 @@
 		rc = my_write(dst_log_fd, log_sys->buf, write_size,
 			      MYF(MY_WME | MY_NABP));
 
+#ifdef USE_POSIX_FADVISE
+		if (!xtrabackup_log_only) {
+			posix_fadvise(dst_log_fd, 0, 0, POSIX_FADV_DONTNEED);
+		}
+#endif
+
 		if(rc) {
 			msg("xtrabackup: Error: write to logfile failed\n");
 			goto error;
@@ -3792,7 +3801,6 @@
 
 #ifdef USE_POSIX_FADVISE
 	posix_fadvise(src_file, 0, 0, POSIX_FADV_SEQUENTIAL);
-	posix_fadvise(src_file, 0, 0, POSIX_FADV_DONTNEED);
 #endif
 
 	if (my_seek(src_file, 0, SEEK_SET, MYF(0)) == MY_FILEPOS_ERROR) {
@@ -3816,6 +3824,9 @@
 	buf = (uchar *) ut_malloc(buf_size);
 
 	while ((bytes = my_read(src_file, buf, buf_size, MYF(MY_WME))) > 0) {
+#ifdef USE_POSIX_FADVISE
+		posix_fadvise(src_file, 0, 0, POSIX_FADV_DONTNEED);
+#endif
 		if (ds->write(dst_file, buf, bytes)) {
 			msg("xtrabackup: error: cannot write to stream "
 			    "for %s.\n", XB_LOG_FILENAME);
@@ -4228,9 +4239,6 @@
 				exit(EXIT_FAILURE);
 			}
 		}
-#ifdef USE_POSIX_FADVISE
-		posix_fadvise(dst_log_fd, 0, 0, POSIX_FADV_DONTNEED);
-#endif
 	} else {
 		dst_log_fd = dup(fileno(stdout));
 		if (dst_log_fd < 0) {