ghost-files: Save device and inode in image

Because we need to lookup for ghost files from
inotify system where we only have device/inode
as a key, we save dev/ino in ghost image entry.

Note we use in-kernel format for device to be
consistent with inotify and mount related
code base.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

files-reg.c

@@ -28,14 +28,11 @@
 struct ghost_file {
 	struct list_head	list;
 	u32			id;
-	union {
-		struct /* for dumping */ {
-			u32	dev;
-			u32	ino;
-		};
-
-		struct file_remap remap; /* for restoring */
-	};
+
+	u32			dev;
+	u32			ino;
+
+	struct file_remap	remap;
 };
 
 static u32 ghost_file_ids = 1;
@@ -83,6 +80,14 @@ static int open_remap_ghost(struct reg_file_info *rfi,
 	if (pb_read_one(ifd, &gfe, PB_GHOST_FILE) < 0)
 		goto close_ifd;
 
+	/*
+	 * For old formats where optional has_[dev|ino] is
+	 * not present we will have zeros here which is quite
+	 * a sign for "absent" fields.
+	 */
+	gf->dev = gfe->dev;
+	gf->ino = gfe->ino;
+
 	snprintf(gf->remap.path, PATH_MAX, "%s.cr.%x.ghost", rfi->path, rfe->remap_id);
 
 	if (S_ISFIFO(gfe->mode)) {
@@ -218,6 +223,10 @@ static int dump_ghost_file(int _fd, u32 id, const struct stat *st)
 	gfe.gid = st->st_gid;
 	gfe.mode = st->st_mode;
 
+	gfe.has_dev = gfe.has_ino = true;
+	gfe.dev = MKKDEV(MAJOR(st->st_dev), MINOR(st->st_dev));
+	gfe.ino = st->st_ino;
+
 	if (pb_write_one(img, &gfe, PB_GHOST_FILE))
 		return -1;
 

include/types.h

@@ -79,6 +79,7 @@ typedef unsigned char		u8;
 typedef signed char		s8;
 
 #define MAJOR(dev)		((dev)>>8)
+#define MINOR(dev)		((dev) & 0xff)
 
 #define _LINUX_CAPABILITY_VERSION_3	0x20080522
 #define _LINUX_CAPABILITY_U32S_3	2

protobuf/ghost-file.proto

@@ -2,4 +2,7 @@ message ghost_file_entry {
 	required uint32		uid		= 1;
 	required uint32		gid		= 2;
 	required uint32		mode		= 3;
+
+	optional uint32		dev		= 4;
+	optional uint64		ino		= 5;
 }