v2 deduplication: add auto-dedup on restore

if option --auto-dedup is set on restore, then as soon as page is
restored it will be punched from the image.

open image in O_RDWR mode
Signed-off-by: Tikhomirov Pavel <snorcht@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-restore.c

@@ -338,9 +338,15 @@ static int restore_priv_vma_content(pid_t pid)
 	struct page_read pr;
 
 	vma = list_first_entry(vmas, struct vma_area, list);
-	ret = open_page_read(pid, &pr);
-	if (ret)
-		return -1;
+	if (!opts.auto_dedup) {
+		ret = open_page_read(pid, &pr);
+		if (ret)
+			return -1;
+	} else {
+		ret = open_page_rw(pid, &pr);
+		if (ret)
+			return -1;
+	}
 
 	/*
 	 * Read page contents.

page-read.c

@@ -3,6 +3,7 @@
 #include <unistd.h>
 
 #include "image.h"
+#include "cr_options.h"
 #include "servicefd.h"
 #include "page-read.h"
 
@@ -146,6 +147,13 @@ static int read_pagemap_page(struct page_read *pr, unsigned long vaddr, void *bu
 			pr_perror("Can't read mapping page %d", ret);
 			return -1;
 		}
+
+		if (opts.auto_dedup) {
+			ret = punch_hole(pr->fd_pg, current_vaddr, (unsigned int)PAGE_SIZE);
+			if (ret == -1) {
+				return -1;
+			}
+		}
 	}
 
 	pr->cvaddr += PAGE_SIZE;