img: Introduce O_FORCE_LOCAL flag for images

 criu/image-desc.c    | 4 ++--
 criu/image.c         | 4 ++--
 criu/include/image.h | 1 +
 3 files changed, 5 insertions(+), 4 deletions(-)

In order to prepare for remote snapshots (possible with Image Proxy and Image
Cache) the O_FORCE_LOCAL flag is added to force some images not to be remote
and stay as local files in the file system.
Signed-off-by: Rodrigo Bruno <rbruno@gsd.inesc-id.pt>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/image-desc.c

@@ -104,13 +104,13 @@ struct cr_fd_desc_tmpl imgset_template[CR_FD_MAX] = {
 	[CR_FD_STATS] = {
 		.fmt	= "stats-%s",
 		.magic	= STATS_MAGIC,
-		.oflags = O_SERVICE,
+		.oflags = O_SERVICE | O_FORCE_LOCAL,
 	},
 
 	[CR_FD_IRMAP_CACHE] = {
 		.fmt	= "irmap-cache",
 		.magic	= IRMAP_CACHE_MAGIC,
-		.oflags = O_SERVICE,
+		.oflags = O_SERVICE | O_FORCE_LOCAL,
 	},
 
 	[CR_FD_FILE_LOCKS_PID] = {

criu/image.c

@@ -371,11 +371,11 @@ static int do_open_image(struct cr_img *img, int dfd, int type, unsigned long of
 {
 	int ret, flags;
 
-	flags = oflags & ~(O_NOBUF | O_SERVICE);
+	flags = oflags & ~(O_NOBUF | O_SERVICE | O_FORCE_LOCAL);
 
 	ret = openat(dfd, path, flags, CR_FD_PERM);
 	if (ret < 0) {
-		if (!(flags & O_CREAT) && (errno == ENOENT)) {
+		if (!(flags & O_CREAT) && (errno == ENOENT || ret == -ENOENT)) {
 			pr_info("No %s image\n", path);
 			img->_x.fd = EMPTY_IMG_FD;
 			goto skip_magic;

criu/include/image.h

@@ -103,6 +103,7 @@ extern bool img_common_magic;
 #define O_DUMP		(O_WRONLY | O_CREAT | O_TRUNC)
 #define O_SHOW		(O_RDONLY | O_NOBUF)
 #define O_RSTR		(O_RDONLY)
+#define O_FORCE_LOCAL	(O_SYNC)
 
 struct cr_img {
 	union {