img: Mark unbufferred images

We have some images that store raw data together with
the pb objects (and one that just stores raw data) and
use custom access to this. E.g. pipe-data images splice
data into them and sk-queue one lseeks the image for
queue packets.

For those using buffered mode mixed with raw may lead
to troubles. Explicitly mark such images, so that the
buffering (next patches) handle such images carefully.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>

image-desc.c

@@ -3,6 +3,7 @@
 #include "image-desc.h"
 #include "cr-show.h"
 #include "magic.h"
+#include "image.h"
 
 /*
  * The cr fd set is the set of files where the information
@@ -17,6 +18,13 @@
 		.magic	= _name##_MAGIC,	\
 	}
 
+#define FD_ENTRY_F(_name, _fmt, _f)		\
+	[CR_FD_##_name] = {			\
+		.fmt	= _fmt ".img",		\
+		.magic	= _name##_MAGIC,	\
+		.oflags	= _f,			\
+	}
+
 struct cr_fd_desc_tmpl imgset_template[CR_FD_MAX] = {
 	FD_ENTRY(INVENTORY,	"inventory"),
 	FD_ENTRY(FDINFO,	"fdinfo-%d"),
@@ -38,16 +46,16 @@ struct cr_fd_desc_tmpl imgset_template[CR_FD_MAX] = {
 	FD_ENTRY(MM,		"mm-%d"),
 	FD_ENTRY(VMAS,		"vmas-%d"),
 	FD_ENTRY(PIPES,		"pipes"),
-	FD_ENTRY(PIPES_DATA,	"pipes-data"),
+	FD_ENTRY_F(PIPES_DATA,	"pipes-data", O_NOBUF), /* splices data */
 	FD_ENTRY(FIFO,		"fifo"),
-	FD_ENTRY(FIFO_DATA,	"fifo-data"),
+	FD_ENTRY_F(FIFO_DATA,	"fifo-data", O_NOBUF), /* the same */
 	FD_ENTRY(PSTREE,	"pstree"),
 	FD_ENTRY(SIGACT,	"sigacts-%d"),
 	FD_ENTRY(UNIXSK,	"unixsk"),
 	FD_ENTRY(INETSK,	"inetsk"),
 	FD_ENTRY(PACKETSK,	"packetsk"),
 	FD_ENTRY(NETLINK_SK,	"netlinksk"),
-	FD_ENTRY(SK_QUEUES,	"sk-queues"),
+	FD_ENTRY_F(SK_QUEUES,	"sk-queues", O_NOBUF), /* lseeks the image */
 	FD_ENTRY(ITIMERS,	"itimers-%d"),
 	FD_ENTRY(POSIX_TIMERS,	"posix-timers-%d"),
 	FD_ENTRY(CREDS,		"creds-%d"),
@@ -58,22 +66,22 @@ struct cr_fd_desc_tmpl imgset_template[CR_FD_MAX] = {
 	FD_ENTRY(IPCNS_SEM,	"ipcns-sem-%d"),
 	FD_ENTRY(FS,		"fs-%d"),
 	FD_ENTRY(REMAP_FPATH,	"remap-fpath"),
-	FD_ENTRY(GHOST_FILE,	"ghost-file-%x"),
+	FD_ENTRY_F(GHOST_FILE,	"ghost-file-%x", O_NOBUF),
 	FD_ENTRY(TCP_STREAM,	"tcp-stream-%x"),
 	FD_ENTRY(MNTS,		"mountpoints-%d"),
 	FD_ENTRY(NETDEV,	"netdev-%d"),
-	FD_ENTRY(IFADDR,	"ifaddr-%d"),
-	FD_ENTRY(ROUTE,		"route-%d"),
-	FD_ENTRY(IPTABLES,	"iptables-%d"),
-	FD_ENTRY(TMPFS_IMG,	"tmpfs-%d.tar.gz"),
-	FD_ENTRY(TMPFS_DEV,	"tmpfs-dev-%d.tar.gz"),
+	FD_ENTRY_F(IFADDR,	"ifaddr-%d", O_NOBUF),
+	FD_ENTRY_F(ROUTE,	"route-%d", O_NOBUF),
+	FD_ENTRY_F(IPTABLES,	"iptables-%d", O_NOBUF),
+	FD_ENTRY_F(TMPFS_IMG,	"tmpfs-%d.tar.gz", O_NOBUF),
+	FD_ENTRY_F(TMPFS_DEV,	"tmpfs-dev-%d.tar.gz", O_NOBUF),
 	FD_ENTRY(TTY_FILES,	"tty"),
 	FD_ENTRY(TTY_INFO,	"tty-info"),
 	FD_ENTRY(FILE_LOCKS,	"filelocks"),
 	FD_ENTRY(RLIMIT,	"rlimit-%d"),
-	FD_ENTRY(PAGES,		"pages-%u"),
-	FD_ENTRY(PAGES_OLD,	"pages-%d"),
-	FD_ENTRY(SHM_PAGES_OLD, "pages-shmem-%ld"),
+	FD_ENTRY_F(PAGES,	"pages-%u", O_NOBUF),
+	FD_ENTRY_F(PAGES_OLD,	"pages-%d", O_NOBUF),
+	FD_ENTRY_F(SHM_PAGES_OLD, "pages-shmem-%ld", O_NOBUF),
 	FD_ENTRY(SIGNAL,	"signal-s-%d"),
 	FD_ENTRY(PSIGNAL,	"signal-p-%d"),
 	FD_ENTRY(TUNFILE,	"tunfile"),

image.c

@@ -211,7 +211,8 @@ struct cr_img *open_image_at(int dfd, int type, unsigned long flags, ...)
 	if (!img)
 		goto errn;
 
-	flags &= ~O_OPT;
+	oflags |= imgset_template[type].oflags;
+	flags &= ~(O_OPT | O_NOBUF);
 
 	va_start(args, flags);
 	vsnprintf(path, PATH_MAX, imgset_template[type].fmt, args);

include/image-desc.h

@@ -101,6 +101,7 @@ enum {
 struct cr_fd_desc_tmpl {
 	const char	*fmt;			/* format for the name */
 	u32		magic;			/* magic in the header */
+	int		oflags;			/* flags for image_open */
 };
 
 extern struct cr_fd_desc_tmpl imgset_template[CR_FD_MAX];

include/image.h

@@ -69,10 +69,12 @@
 extern bool fdinfo_per_id;
 extern bool ns_per_id;
 
+#define O_OPT	(O_PATH)
+#define O_NOBUF	(O_DIRECT)
+
 #define O_DUMP	(O_RDWR | O_CREAT | O_TRUNC)
-#define O_SHOW	(O_RDONLY)
+#define O_SHOW	(O_RDONLY | O_NOBUF)
 #define O_RSTR	(O_RDONLY)
-#define O_OPT	(O_PATH)
 
 struct cr_img {
 	int _fd;