files: dump fdinfo per files_id instead of pid

A few processes can share one fdtable.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -355,10 +355,10 @@ static int dump_one_file(struct parasite_ctl *ctl, int fd, int lfd, struct fd_op
 	return dump_unsupp_fd(&p);
 }
 
-static int dump_task_files_seized(struct parasite_ctl *ctl, const int fdinfo,
+static int dump_task_files_seized(struct parasite_ctl *ctl, struct pstree_item *item,
 		struct parasite_drain_fd *dfds)
 {
-	int *lfds;
+	int *lfds, fdinfo;
 	struct fd_opts *opts;
 	int i, ret = -1;
 
@@ -378,13 +378,19 @@ static int dump_task_files_seized(struct parasite_ctl *ctl, const int fdinfo,
 	if (ret)
 		goto err2;
 
+	fdinfo = open_image(CR_FD_FDINFO, O_DUMP, item->ids->files_id);
+	if (fdinfo < 0)
+		goto err2;
+
 	for (i = 0; i < dfds->nr_fds; i++) {
 		ret = dump_one_file(ctl, dfds->fds[i], lfds[i], opts + i, fdinfo);
 		close(lfds[i]);
 		if (ret)
-			goto err2;
+			break;
 	}
 
+	close(fdinfo);
+
 	pr_info("----------------------------------------\n");
 err2:
 	xfree(opts);
@@ -1453,7 +1459,13 @@ static int dump_one_task(struct pstree_item *item)
 	if (!cr_fdset)
 		goto err_cure;
 
-	ret = dump_task_files_seized(parasite_ctl, fdset_fd(cr_fdset, CR_FD_FDINFO), dfds);
+	ret = dump_task_ids(item, cr_fdset);
+	if (ret) {
+		pr_err("Dump ids (pid: %d) failed with %d\n", pid, ret);
+		goto err_cure;
+	}
+
+	ret = dump_task_files_seized(parasite_ctl, item, dfds);
 	if (ret) {
 		pr_err("Dump files (pid: %d) failed with %d\n", pid, ret);
 		goto err_cure;
@@ -1484,12 +1496,6 @@ static int dump_one_task(struct pstree_item *item)
 		goto err_cure;
 	}
 
-	ret = dump_task_ids(item, cr_fdset);
-	if (ret) {
-		pr_err("Dump ids (pid: %d) failed with %d\n", pid, ret);
-		goto err_cure;
-	}
-
 	ret = dump_task_threads(parasite_ctl, item);
 	if (ret) {
 		pr_err("Can't dump threads\n");

cr-restore.c

@@ -156,7 +156,7 @@ static int root_prepare_shared(void)
 		if (ret < 0)
 			break;
 
-		ret = prepare_fd_pid(pi->pid.virt, pi->rst);
+		ret = prepare_fd_pid(pi);
 		if (ret < 0)
 			break;
 	}

files.c

@@ -217,19 +217,32 @@ int prepare_ctl_tty(int pid, struct rst_info *rst_info, u32 ctl_tty_id)
 	return 0;
 }
 
-int prepare_fd_pid(int pid, struct rst_info *rst_info)
+int prepare_fd_pid(struct pstree_item *item)
 {
 	int fdinfo_fd, ret = 0;
+	pid_t pid = item->pid.virt;
+	struct rst_info *rst_info = item->rst;
 
 	INIT_LIST_HEAD(&rst_info->fds);
 	INIT_LIST_HEAD(&rst_info->eventpoll);
 	INIT_LIST_HEAD(&rst_info->tty_slaves);
 
-	fdinfo_fd = open_image_ro(CR_FD_FDINFO, pid);
-	if (fdinfo_fd < 0) {
-		if (errno == ENOENT)
+	if (!fdinfo_per_id) {
+		fdinfo_fd = open_image_ro(CR_FD_FDINFO, pid);
+		if (fdinfo_fd < 0) {
+			if (errno == ENOENT)
+				return 0;
+			return -1;
+		}
+	} else {
+		if (item->ids == NULL) /* zombie */
 			return 0;
-		else
+
+		if (item->rst->fdt && item->rst->fdt->pid != item->pid.virt)
+			return 0;
+
+		fdinfo_fd = open_image_ro(CR_FD_FDINFO, item->ids->files_id);
+		if (fdinfo_fd < 0)
 			return -1;
 	}
 

image.c

@@ -15,6 +15,8 @@
 #include "protobuf.h"
 #include "protobuf/inventory.pb-c.h"
 
+bool fdinfo_per_id = false;
+
 int check_img_inventory(void)
 {
 	int fd, ret;
@@ -29,6 +31,8 @@ int check_img_inventory(void)
 	if (ret < 0)
 		return ret;
 
+	fdinfo_per_id = he->has_fdinfo_per_id ?  he->fdinfo_per_id : false;
+
 	ret = he->img_version;
 	inventory_entry__free_unpacked(he, NULL);
 
@@ -52,6 +56,8 @@ int write_img_inventory(void)
 		return -1;
 
 	he.img_version = CRTOOLS_IMAGES_V1;
+	he.fdinfo_per_id = true;
+	he.has_fdinfo_per_id = true;
 
 	if (pb_write_one(fd, &he, PB_INVENTORY) < 0)
 		return -1;

include/crtools.h

@@ -24,7 +24,6 @@ enum {
 	 */
 
 	_CR_FD_TASK_FROM,
-	CR_FD_FDINFO,
 	CR_FD_PAGES,
 	CR_FD_CORE,
 	CR_FD_IDS,
@@ -57,6 +56,7 @@ enum {
 	CR_FD_SHMEM_PAGES,
 	CR_FD_GHOST_FILE,
 	CR_FD_TCP_STREAM,
+	CR_FD_FDINFO,
 
 	_CR_FD_GLOB_FROM,
 	CR_FD_SK_QUEUES,

include/files.h

@@ -87,7 +87,7 @@ extern int rst_file_params(int fd, FownEntry *fown, int flags);
 extern void show_saved_files(void);
 
 extern int prepare_fds(struct pstree_item *me);
-extern int prepare_fd_pid(int pid, struct rst_info *rst_info);
+extern int prepare_fd_pid(struct pstree_item *me);
 extern int prepare_ctl_tty(int pid, struct rst_info *rst_info, u32 ctl_tty_id);
 extern int prepare_shared_fdinfo(void);
 extern int get_filemap_fd(int pid, VmaEntry *vma_entry);

include/image.h

@@ -135,4 +135,6 @@ struct page_entry {
 #define GET_FILE_OFF(s, m)	(offsetof(s,m) + MAGIC_OFFSET)
 #define GET_FILE_OFF_AFTER(s)	(sizeof(s) + MAGIC_OFFSET)
 
+extern bool fdinfo_per_id;
+
 #endif /* __CR_IMAGE_H__ */

protobuf/inventory.proto

 message inventory_entry {
 	required uint32	img_version = 1;
+	optional bool fdinfo_per_id = 2;
 }