Merge lp:~akopytov/percona-xtrabackup/bug1177201-2.1 into lp:percona-xtrabackup/2.1

[Alexey Kopytov]

    Bug #1177201: Assertion "to_read % cursor->page_size == 0" failed at
                  fil_cur.cc:218

    Allow junk at the end of data files, i.e. when there’s a block less than
    the page size at the end of the file. It is apparently a server-side
    problem with unknown root cause, but it’s ok to ignore that as long as
    InnoDB itself ignores such datafiles.

http://jenkins.percona.com/view/PXB%202.1/job/percona-xtrabackup-2.1-param/553/

[Sergei Glushchenko (sergei.glushchenko)]

Hi Alexey,

Looks good, but please resubmit to lp:percona-xtrabackup/2.1

review: Needs Resubmitting (g2)

[Sergei Glushchenko (sergei.glushchenko)]

Approve

review: Approve (g2)

[Alexey Kopytov (akopytov)]

Hm, there's a problem: if to_read is not a multiple of the page size, but is more than the page size (i.e. there are still some full pages in the requested block), we are going to lose some data by not copying the entire block.

[Alexey Kopytov (akopytov)]

review: Approve

=== modified file 'src/fil_cur.cc'
--- src/fil_cur.cc	2013-08-18 06:54:14 +0000
+++ src/fil_cur.cc	2014-03-01 13:06:22 +0000
@@ -289,7 +289,28 @@
 	if (to_read > (ib_int64_t) cursor->buf_size) {
 		to_read = (ib_int64_t) cursor->buf_size;
 	}
+
 	xb_a(to_read > 0 && to_read <= 0xFFFFFFFFLL);
+
+	if (to_read % cursor->page_size != 0 &&
+	    offset + to_read == cursor->statinfo.st_size) {
+
+		if (to_read < (ib_int64_t) cursor->page_size) {
+			msg("[%02u] xtrabackup: Warning: junk at the end of "
+			    "%s:\n", cursor->thread_n, cursor->abs_path);
+			msg("[%02u] xtrabackup: Warning: offset = %llu, "
+			    "to_read = %llu\n",
+			    cursor->thread_n,
+			    (unsigned long long) offset,
+			    (unsigned long long) to_read);
+
+			return(XB_FIL_CUR_EOF);
+		}
+
+		to_read = (ib_int64_t) (((ulint) to_read) &
+					~(cursor->page_size - 1));
+	}
+
 	xb_a(to_read % cursor->page_size == 0);
 
 	npages = (ulint) (to_read >> cursor->page_size_shift);

=== added file 'test/t/bug1177201.sh'
--- test/t/bug1177201.sh	1970-01-01 00:00:00 +0000
+++ test/t/bug1177201.sh	2014-03-01 13:06:22 +0000
@@ -0,0 +1,22 @@
+########################################################################
+# Bug #1177201: Assertion "to_read % cursor->page_size == 0" failed at
+#               fil_cur.cc:218
+########################################################################
+
+start_server
+
+dd if=/dev/zero of=$topdir/zeroes bs=1 count=4096
+
+cat $topdir/zeroes >>$MYSQLD_DATADIR/ibdata1
+
+innobackupex --no-timestamp $topdir/backup
+
+stop_server
+
+rm -rf $MYSQLD_DATADIR/*
+
+innobackupex --apply-log $topdir/backup
+
+innobackupex --copy-back $topdir/backup
+
+start_server