[CRIU] [PATCH RFC v3 2/4] mem: Introduce image-proxy/image-cache & remote option
Katerina Koukiou
k.koukiou at googlemail.com
Sun Aug 14 05:55:44 PDT 2016
On Fri, Aug 12, 2016 at 2:16 PM, Pavel Emelyanov <xemul at virtuozzo.com> wrote:
> On 08/10/2016 04:19 PM, Katerina Koukiou wrote:
>> This patch introduces --remote option and image-proxy/image-cache processes.
>> This leaves user the option to decide if the checkpoint data are to be stored
>> on disk or sent through socket to the image-proxy.
>> The latter forwards the data to the destination node where image-cache receives
>> them.
>>
>> The overall communication is performed as follows:
>> rc_node CRIU dump -> (sends images using a local socket) -> image-proxy
>> |
>> V
>> dst_node: CRIU restore <- (receives images from a local socket) <- image-cache
>>
>> Running criu with --remote option is like this:
>>
>> dst_node# criu image-cache --port <port> -o /tmp/image-cache.log
>> --local-cache-path <local_cache_path> ...
>> dst_node# criu restore --remote -o /tmp/image-cache.log
>> --local-cache-path <local_cache_path> ...
>> src_node# criu image-proxy --port <port> --address <dst_node> -o /tmp/image-proxy.log
>> --local-proxy-path <local_proxy_path> ...
>> src_node# criu dump -t <pid> --remote -o /tmp/dump.log
>> --local-proxy-path <local_proxy_path> ...
>
> Katerina, thanks A LOT for picking this up :) Please, find my comments inline.
> I remember that you do it as a part of you GSoC project, how much time do
> you still have to play with it?
Pavel, thanks for being open to new patches as well :)The project unfortunately
is finishing in a week from now.But I 'll try to continue with that.
And having t
hese patches functional is a good start :)
>
>> Signed-off-by: Rodrigo Bruno <rbruno at gsd.inesc-id.pt>
>> Signed-off-by: Katerina Koukiou <k.koukiou at gmail.com>
>> ---
>> criu/Makefile.crtools | 4 +
>> criu/cr-dump.c | 17 +++
>> criu/crtools.c | 30 ++++-
>> criu/image-desc.c | 4 +-
>> criu/image.c | 28 ++++-
>> criu/img-remote-proto.c | 4 +
>> criu/img-remote.c | 278 +++++++++++++++++++++++++++++++++++++++++++
>> criu/include/cr_options.h | 3 +
>> criu/include/image.h | 1 +
>> criu/include/img-remote.h | 79 ++++++++++++
>> criu/include/protobuf-desc.h | 4 +
>> criu/page-xfer.c | 26 +++-
>> criu/pagemap.c | 53 +++++++--
>> criu/protobuf-desc.c | 1 +
>> images/Makefile | 1 +
>> images/remote-image.proto | 20 ++++
>> 16 files changed, 529 insertions(+), 24 deletions(-)
>
> Although I don't argue these patches work :) this is too much for a
> single patch. Let's try to split it into pieces.
>
> Suggestions on how to split and other comments below.
Thanks for that
>
>> create mode 100644 criu/img-remote.c
>> create mode 100644 criu/include/img-remote.h
>> create mode 100644 images/remote-image.proto
>>
>> diff --git a/criu/Makefile.crtools b/criu/Makefile.crtools
>> index 8e9c3b4..95a0521 100644
>> --- a/criu/Makefile.crtools
>> +++ b/criu/Makefile.crtools
>> @@ -26,6 +26,10 @@ obj-y += files-reg.o
>> obj-y += fsnotify.o
>> obj-y += image-desc.o
>> obj-y += image.o
>> +obj-y += img-remote.o
>> +obj-y += img-proxy.o
>> +obj-y += img-cache.o
>> +obj-y += img-remote-proto.o
>> obj-y += ipc_ns.o
>> obj-y += irmap.o
>> obj-y += kcmp-ids.o
>> diff --git a/criu/cr-dump.c b/criu/cr-dump.c
>> index 06ff2d7..5b5a232 100644
>> --- a/criu/cr-dump.c
>> +++ b/criu/cr-dump.c
>> @@ -84,6 +84,8 @@
>>
>> #include "asm/dump.h"
>>
>> +#include "img-remote.h"
>> +
>> static char loc_buf[PAGE_SIZE];
>>
>> void free_mappings(struct vm_area_list *vma_area_list)
>> @@ -1504,6 +1506,11 @@ int cr_pre_dump_tasks(pid_t pid)
>> struct pstree_item *item;
>> int ret = -1;
>>
>> + if (opts.remote && push_snapshot_id() < 0) {
>> + pr_err("Failed to push image namespace.\n");
>> + goto err;
>> + }
>> +
>> root_item = alloc_pstree_item();
>> if (!root_item)
>> goto err;
>> @@ -1660,6 +1667,11 @@ static int cr_dump_finish(int ret)
>>
>> close_service_fd(CR_PROC_FD_OFF);
>>
>> + if (opts.remote && (finish_remote_dump() < 0)) {
>> + pr_err("Finish remote dump failed.\n");
>> + return post_dump_ret ? : 1;
>> + }
>> +
>> if (ret) {
>> pr_err("Dumping FAILED.\n");
>> } else {
>> @@ -1680,6 +1692,11 @@ int cr_dump_tasks(pid_t pid)
>> pr_info("Dumping processes (pid: %d)\n", pid);
>> pr_info("========================================\n");
>>
>> + if (opts.remote && push_snapshot_id() < 0) {
>> + pr_err("Failed to push image namespace.\n");
>> + goto err;
>> + }
>> +
>> root_item = alloc_pstree_item();
>> if (!root_item)
>> goto err;
>> diff --git a/criu/crtools.c b/criu/crtools.c
>> index 7e11c22..2d1ece2 100644
>> --- a/criu/crtools.c
>> +++ b/criu/crtools.c
>> @@ -48,6 +48,7 @@
>> #include "namespaces.h"
>> #include "setproctitle.h"
>> #include "sysctl.h"
>> +#include "img-remote.h"
>>
>> struct cr_options opts;
>>
>> @@ -72,6 +73,10 @@ void init_opts(void)
>> opts.ghost_limit = DEFAULT_GHOST_LIMIT;
>> opts.timeout = DEFAULT_TIMEOUT;
>> opts.empty_ns = 0;
>> + opts.addr = DEFAULT_CACHE_HOST;
>> + opts.port = DEFAULT_CACHE_PORT;
>> + opts.local_cache_path = DEFAULT_IMG_PATH;
>> + opts.local_proxy_path = DEFAULT_IMG_PATH;
>> }
>>
>> static int parse_join_ns(const char *ptr)
>> @@ -324,6 +329,9 @@ int main(int argc, char *argv[], char *envp[])
>> { "cgroup-props-file", required_argument, 0, 1081 },
>> { "cgroup-dump-controller", required_argument, 0, 1082 },
>> { SK_INFLIGHT_PARAM, no_argument, 0, 1083 },
>> + { "remote", no_argument, 0, 1084 },
>> + { "local-cache-path", required_argument, 0, 1085 },
>> + { "local-proxy-path", required_argument, 0, 1086 },
>
> These are paths to sockets, aren't they? We've had the same functionality
> in lazy-restore and decided to drop configurable paths to sockets and
> just put sockets with hard-coded names into work-dir.
Ok
>
>> { },
>> };
>>
>> @@ -639,6 +647,15 @@ int main(int argc, char *argv[], char *envp[])
>> pr_msg("Will skip in-flight TCP connections\n");
>> opts.tcp_skip_in_flight = true;
>> break;
>> + case 1084:
>> + opts.remote = true;
>> + break;
>> + case 1085:
>> + opts.local_cache_path = optarg;
>> + break;
>> + case 1086:
>> + opts.local_proxy_path = optarg;
>> + break;
>> case 'V':
>> pr_msg("Version: %s\n", CRIU_VERSION);
>> if (strcmp(CRIU_GITID, "0"))
>> @@ -794,6 +811,12 @@ int main(int argc, char *argv[], char *envp[])
>> if (!strcmp(argv[optind], "page-server"))
>> return cr_page_server(opts.daemon_mode, -1) > 0 ? 0 : 1;
>>
>> + if (!strcmp(argv[optind], "image-cache"))
>> + return image_cache(opts.local_cache_path, opts.port);
>> +
>> + if (!strcmp(argv[optind], "image-proxy"))
>> + return image_proxy(opts.local_proxy_path, opts.addr, opts.port);
>> +
>> if (!strcmp(argv[optind], "service"))
>> return cr_service(opts.daemon_mode);
>>
>> @@ -821,6 +844,8 @@ usage:
>> " criu service [<options>]\n"
>> " criu dedup\n"
>> " criu lazy-pages -D DIR [<options>]\n"
>> +" criu image-cache [<options>]\n"
>> +" criu image-proxy [<options>]\n"
>> "\n"
>> "Commands:\n"
>> " dump checkpoint a process/tree identified by pid\n"
>> @@ -833,6 +858,8 @@ usage:
>> " dedup remove duplicates in memory dump\n"
>> " cpuinfo dump writes cpu information into image file\n"
>> " cpuinfo check validates cpu information read from image file\n"
>> +" image-cache launch destination-side cache for images sent from the source-side\n"
>> +" image-proxy launch source-side proxy to sent images to the destination-side\n"
>> );
>>
>> if (usage_error) {
>> @@ -864,6 +891,7 @@ usage:
>> " this requires running a second instance of criu\n"
>> " in lazy-pages mode: 'criu lazy-pages -D DIR'\n"
>> " --lazy-pages and lazy-pages mode require userfaultfd\n"
>> +" --remote dump/restore images directly to/from remote node using image-proxy/image-cache\n"
>> "\n"
>> "* Special resources support:\n"
>> " -x|--" USK_EXT_PARAM "inode,.." " allow external unix connections (optionally can be assign socket's inode that allows one-sided dump)\n"
>> @@ -973,7 +1001,7 @@ usage:
>> "\n"
>> "Page/Service server options:\n"
>> " --address ADDR address of server or service\n"
>> -" --port PORT port of page server\n"
>> +" --port PORT port of page serve or service\n"
>> " -d|--daemon run in the background after creating socket\n"
>> "\n"
>> "Other options:\n"
>> diff --git a/criu/image-desc.c b/criu/image-desc.c
>> index 2b31354..e146ef8 100644
>> --- a/criu/image-desc.c
>> +++ b/criu/image-desc.c
>> @@ -102,13 +102,13 @@ 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,
>
> Please, introduce the O_FORCE_LOCAL flag with separate patch.
>
Sure
>> },
>>
>> [CR_FD_FILE_LOCKS_PID] = {
>> diff --git a/criu/image.c b/criu/image.c
>> index a3bb285..38a8ea9 100644
>> --- a/criu/image.c
>> +++ b/criu/image.c
>> @@ -13,6 +13,7 @@
>> #include "protobuf.h"
>> #include "images/inventory.pb-c.h"
>> #include "images/pagemap.pb-c.h"
>> +#include "img-remote.h"
>>
>> bool ns_per_id = false;
>> bool img_common_magic = true;
>> @@ -309,11 +310,28 @@ 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 (opts.remote && !(oflags & O_FORCE_LOCAL)) {
>> + char *snapshot_id = NULL;
>> +
>> + snapshot_id = get_snapshot_id_from_idx(dfd);
>> +
>> + if (snapshot_id == NULL)
>> + ret = -1;
>> + else if (flags == O_RDONLY) {
>> + pr_debug("do_open_remote_image RDONLY path=%s snapshot_id=%s\n",
>> + path, snapshot_id);
>> + ret = read_remote_image_connection(snapshot_id, path);
>> + } else {
>> + pr_debug("do_open_remote_image WDONLY path=%s snapshot_id=%s\n",
>> + path, snapshot_id);
>> + ret = write_remote_image_connection(snapshot_id, path, O_WRONLY);
>> + }
>
> Can we have this if () branch moved into a separate helper function?
ok
>
>> + } else
>> + 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;
>> @@ -413,7 +431,9 @@ int open_image_dir(char *dir)
>> close(fd);
>> fd = ret;
>>
>> - if (opts.img_parent) {
>> + if (opts.remote) {
>> + init_snapshot_id(dir);
>> + } else if (opts.img_parent) {
>> ret = symlinkat(opts.img_parent, fd, CR_PARENT_LINK);
>> if (ret < 0 && errno != EEXIST) {
>> pr_perror("Can't link parent snapshot");
>> diff --git a/criu/img-remote-proto.c b/criu/img-remote-proto.c
>> index d8fd8cd..19cfe35 100644
>> --- a/criu/img-remote-proto.c
>> +++ b/criu/img-remote-proto.c
>> @@ -236,6 +236,10 @@ int setup_TCP_client_socket(char *hostname, int port)
>>
>> int setup_UNIX_server_socket(char *path)
>> {
>> + if (!path) {
>> + pr_err("Path should not be empty\n");
>> + return -1;
>> + }
>
> This fixlet in separate patch, please.
If I make the path hardcoded as you suggested this won't be needed I think.
>
>> struct sockaddr_un addr;
>> int sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
>>
>> diff --git a/criu/img-remote.c b/criu/img-remote.c
>> new file mode 100644
>> index 0000000..9e244c6
>> --- /dev/null
>> +++ b/criu/img-remote.c
>> @@ -0,0 +1,278 @@
>> +#include <unistd.h>
>> +#include <stdlib.h>
>> +#include <sys/types.h>
>> +#include <sys/socket.h>
>> +#include <netinet/in.h>
>> +#include <netdb.h>
>> +#include "xmalloc.h"
>> +#include "criu-log.h"
>> +#include "img-remote.h"
>> +#include "img-remote-proto.h"
>> +#include "images/remote-image.pb-c.h"
>> +#include "protobuf-desc.h"
>> +#include <fcntl.h>
>> +#include "servicefd.h"
>> +#include "compiler.h"
>> +#include "cr_options.h"
>> +
>> +#define PB_LOCAL_IMAGE_SIZE PATHLEN
>> +
>> +static char *snapshot_id;
>> +
>> +LIST_HEAD(snapshot_head);
>> +
>> +/* A snapshot is a dump or pre-dump operation. Each snapshot is identified by an
>> + * ID which corresponds to the working directory specefied by the user.
>> + */
>> +struct snapshot {
>> + char snapshot_id[PATHLEN];
>> + struct list_head l;
>> +};
>> +
>> +struct snapshot *new_snapshot(char *snapshot_id)
>> +{
>> + struct snapshot *s = malloc(sizeof(struct snapshot));
>> +
>> + if (!s) {
>> + pr_perror("Failed to allocate snapshot structure");
>> + return NULL;
>> + }
>> + strncpy(s->snapshot_id, snapshot_id, PATHLEN);
>> + return s;
>> +}
>> +
>> +void add_snapshot(struct snapshot *snapshot)
>> +{
>> + list_add_tail(&(snapshot->l), &snapshot_head);
>> +}
>> +
>> +static char *get_local_img_path(void)
>> +{
>> + static char *local_img_path = NULL;
>> +
>> + if (local_img_path != NULL)
>> + return local_img_path;
>> +
>> + if (strcmp(opts.local_cache_path, DEFAULT_IMG_PATH))
>> + local_img_path = opts.local_cache_path;
>> + else if (strcmp(opts.local_proxy_path, DEFAULT_IMG_PATH))
>> + local_img_path = opts.local_proxy_path;
>> + else if (opts.local_proxy_path || opts.local_cache_path)
>> + local_img_path = DEFAULT_IMG_PATH;
>> + else
>> + pr_err("Local img path is missing. Possible missing "
>> + "--local-{cache,proxy}-path option\n");
>> +
>> + return local_img_path;
>> +}
>> +
>> +int read_remote_image_connection(char *snapshot_id, char *path)
>> +{
>> + int error;
>> + int sockfd = setup_UNIX_client_socket(get_local_img_path());
>> +
>> + if (sockfd < 0) {
>> + pr_perror("Error opening local connection for %s:%s", path, snapshot_id);
>> + return -1;
>> + }
>> +
>> + if (write_header(sockfd, snapshot_id, path, O_RDONLY) < 0) {
>> + pr_perror("Error writing header for %s:%s", path, snapshot_id);
>> + return -1;
>> + }
>> +
>> + if (read_reply_header(sockfd, &error) < 0) {
>> + pr_perror("Error reading reply header for %s:%s", path, snapshot_id);
>> + return -1;
>> + }
>> + if (!error)
>> + return sockfd;
>> + else if (error == ENOENT) {
>> + pr_info("Image does not exist (%s:%s)\n", path, snapshot_id);
>> + close(sockfd);
>> + return -ENOENT;
>> + }
>> + pr_perror("Unexpected error returned: %d (%s:%s)\n", error, path, snapshot_id);
>> + close(sockfd);
>> + return -1;
>> +}
>> +
>> +int write_remote_image_connection(char *snapshot_id, char *path, int flags)
>> +{
>> + int sockfd = setup_UNIX_client_socket(get_local_img_path());
>> +
>> + if (sockfd < 0)
>> + return -1;
>> +
>> + if (write_header(sockfd, snapshot_id, path, flags) < 0) {
>> + pr_perror("Error writing header for %s:%s", path, snapshot_id);
>> + return -1;
>> + }
>> + return sockfd;
>> +}
>> +
>> +int finish_remote_dump(void)
>> +{
>> + pr_info("Dump side is calling finish\n");
>> + int fd = write_remote_image_connection(NULL_SNAPSHOT_ID, DUMP_FINISH, O_WRONLY);
>> +
>> + if (fd == -1) {
>> + pr_perror("Unable to open finish dump connection");
>> + return -1;
>> + }
>> +
>> + close(fd);
>> + return 0;
>> +}
>> +
>> +int skip_remote_bytes(int fd, unsigned long len)
>> +{
>> + static char buf[4096];
>> + int n = 0;
>> + unsigned long curr = 0;
>> +
>> + for (; curr < len; ) {
>> + n = read(fd, buf, min(len - curr, (unsigned long)4096));
>> + if (n == 0) {
>> + pr_perror("Unexpected end of stream (skipping %lx/%lx bytes)",
>> + curr, len);
>> + return -1;
>> + } else if (n > 0) {
>> + curr += n;
>> + } else {
>> + pr_perror("Error while skipping bytes from stream (%lx/%lx)",
>> + curr, len);
>> + return -1;
>> + }
>> + }
>> +
>> + if (curr != len) {
>> + pr_perror("Unable to skip the current number of bytes: %lx instead of %lx",
>> + curr, len);
>> + return -1;
>> + }
>> + return 0;
>> +}
>> +
>> +static int pull_snapshot_ids(void)
>> +{
>> + int n, sockfd;
>> + SnapshotIdEntry *ls;
>> + struct snapshot *s = NULL;
>> +
>> + sockfd = read_remote_image_connection(NULL_SNAPSHOT_ID, PARENT_IMG);
>> +
>> + /* The connection was successful but there is not file. */
>> + if (sockfd < 0 && errno == ENOENT)
>> + return 0;
>> + else if (sockfd < 0) {
>> + pr_perror("Unable to open snapshot id read connection");
>> + return -1;
>> + }
>> +
>> + while (1) {
>> + n = pb_read_obj(sockfd, (void **)&ls, PB_SNAPSHOT_ID);
>> + if (!n) {
>> + close(sockfd);
>> + return n;
>> + } else if (n < 0) {
>> + pr_perror("Unable to read remote snapshot ids");
>> + close(sockfd);
>> + return n;
>> + }
>> +
>> + s = new_snapshot(ls->snapshot_id);
>> + if (!s) {
>> + pr_perror("Unable create new snapshot structure");
>> + close(sockfd);
>> + return -1;
>> + }
>> + add_snapshot(s);
>> + pr_info("[read_snapshot ids] parent = %s\n", ls->snapshot_id);
>> + }
>> + free(ls);
>> + close(sockfd);
>> + return n;
>> +}
>> +
>> +int push_snapshot_id(void)
>> +{
>> + int n;
>> + SnapshotIdEntry rn = SNAPSHOT_ID_ENTRY__INIT;
>> + int sockfd = write_remote_image_connection(NULL_SNAPSHOT_ID, PARENT_IMG, O_APPEND);
>> +
>> + if (sockfd < 0) {
>> + pr_perror("Unable to open snapshot id push connection");
>> + return -1;
>> + }
>> +
>> + rn.snapshot_id = xmalloc(sizeof(char) * PATHLEN);
>> + if (!rn.snapshot_id) {
>> + pr_perror("Unable to allocate snapshot id buffer");
>> + close(sockfd);
>> + return -1;
>> + }
>> + strncpy(rn.snapshot_id, snapshot_id, PATHLEN);
>> +
>> + n = pb_write_obj(sockfd, &rn, PB_SNAPSHOT_ID);
>> +
>> + xfree(rn.snapshot_id);
>> + close(sockfd);
>> + return n;
>> +}
>> +
>> +void init_snapshot_id(char *si)
>> +{
>> + snapshot_id = si;
>> +}
>> +
>> +char *get_curr_snapshot_id(void)
>> +{
>> + return snapshot_id;
>> +}
>> +
>> +int get_curr_snapshot_id_idx(void)
>> +{
>> + struct snapshot *si;
>> + int idx = 0;
>> +
>> + if (list_empty(&snapshot_head))
>> + pull_snapshot_ids();
>> +
>> + list_for_each_entry(si, &snapshot_head, l) {
>> + if (!strncmp(si->snapshot_id, snapshot_id, PATHLEN))
>> + return idx;
>> + idx++;
>> + }
>> +
>> + pr_perror("Error, could not find current snapshot id (%s) fd", snapshot_id);
>> + return -1;
>> +}
>> +
>> +char *get_snapshot_id_from_idx(int idx)
>> +{
>> + struct snapshot *si;
>> +
>> + if (list_empty(&snapshot_head))
>> + pull_snapshot_ids();
>> +
>> + /* Note: if idx is the service fd then we need the current
>> + * snapshot_id idx. Else we need a parent snapshot_id idx.
>> + */
>> + if (idx == get_service_fd(IMG_FD_OFF))
>> + idx = get_curr_snapshot_id_idx();
>> +
>> + list_for_each_entry(si, &snapshot_head, l) {
>> + if (!idx)
>> + return si->snapshot_id;
>> + idx--;
>> + }
>> +
>> + pr_perror("Error, could not find snapshot id for idx %d", idx);
>> + return NULL;
>> +}
>> +
>> +int get_curr_parent_snapshot_id_idx(void)
>> +{
>> + return get_curr_snapshot_id_idx() - 1;
>> +}
>> diff --git a/criu/include/cr_options.h b/criu/include/cr_options.h
>> index 35c1ace..6f1b202 100644
>> --- a/criu/include/cr_options.h
>> +++ b/criu/include/cr_options.h
>> @@ -113,6 +113,9 @@ struct cr_options {
>> bool lazy_pages;
>> bool tcp_skip_in_flight;
>> char *work_dir;
>> + bool remote;
>> + char *local_cache_path;
>> + char *local_proxy_path;
>> };
>>
>> extern struct cr_options opts;
>> diff --git a/criu/include/image.h b/criu/include/image.h
>> index 65b7b0a..9ba6ab8 100644
>> --- a/criu/include/image.h
>> +++ b/criu/include/image.h
>> @@ -104,6 +104,7 @@ 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 {
>> diff --git a/criu/include/img-remote.h b/criu/include/img-remote.h
>> new file mode 100644
>> index 0000000..706b67f
>> --- /dev/null
>> +++ b/criu/include/img-remote.h
>> @@ -0,0 +1,79 @@
>> +#include <limits.h>
>> +
>> +#ifndef IMAGE_REMOTE_H
>> +#define IMAGE_REMOTE_H
>> +
>> +#define PATHLEN PATH_MAX
>> +#define DUMP_FINISH "DUMP_FINISH"
>> +#define PARENT_IMG "parent"
>> +#define NULL_SNAPSHOT_ID "null"
>> +#define DEFAULT_IMG_PATH "/tmp/criu-img-path.sock"
>> +#define DEFAULT_CACHE_PORT 9996
>> +#define DEFAULT_CACHE_HOST "localhost"
>> +
>> +/* Called by restore to get the fd correspondent to a particular path. This call
>> + * will block until the connection is received.
>> + */
>> +int read_remote_image_connection(char *snapshot_id, char *path);
>> +
>> +/* Called by dump to create a socket connection to the restore side. The socket
>> + * fd is returned for further writing operations.
>> + */
>> +int write_remote_image_connection(char *snapshot_id, char *path, int flags);
>> +
>> +/* Called by dump when everything is dumped. This function creates a new
>> + * connection with a special control name. The recover side uses it to ack that
>> + * no more files are coming.
>> + */
>> +int finish_remote_dump();
>> +
>> +/* Starts an image proxy daemon (dump side). It receives image files through
>> + * socket connections and forwards them to the image cache (restore side).
>> + */
>> +int image_proxy(char *local_proxy_path, char *cache_host, unsigned short cache_port);
>> +
>> +/* Starts an image cache daemon (restore side). It receives image files through
>> + * socket connections and caches them until they are requested by the restore
>> + * process.
>> + */
>> +int image_cache(char *local_cache_path, unsigned short cache_port);
>> +
>> +/* Reads (discards) 'len' bytes from fd. This is used to emulate the function
>> + * lseek, which is used to advance the file needle.
>> + */
>> +int skip_remote_bytes(int fd, unsigned long len);
>> +
>> +/* To support iterative migration, the concept of snapshot_id is introduced
>> + * (only when remote migration is enabled). Each image is tagged with one
>> + * snapshot_id. The snapshot_id is the image directory used for the operation
>> + * that creates the image (either predump or dump). Images stored in memory
>> + * (both in Image Proxy and Image Cache) are identified by their name and
>> + * snapshot_id. Snapshot_ids are ordered so that we can find parent pagemaps
>> + * (that will be used when restoring the process).
>> + */
>> +
>> +/* Sets the current snapshot_id */
>> +void init_snapshot_id(char *ns);
>> +
>> +/* Returns the current snapshot_id. */
>> +char *get_curr_snapshot_id();
>> +
>> +/* Returns the snapshot_id index representing the current snapshot_id. This
>> + * index represents the hierarchy position. For example: images tagged with
>> + * the snapshot_id with index 1 are more recent than the images tagged with
>> + * the snapshot_id with index 0.
>> + */
>> +int get_curr_snapshot_id_idx();
>> +
>> +/* Returns the snapshot_id associated with the snapshot_id index. */
>> +char *get_snapshot_id_from_idx(int idx);
>> +
>> +/* Pushes the current snapshot_id into the snapshot_id hierarchy (into the Image
>> + * Proxy and Image Cache).
>> + */
>> +int push_snapshot_id();
>> +
>> +/* Returns the snapshot id index that preceeds the current snapshot_id. */
>> +int get_curr_parent_snapshot_id_idx();
>> +
>> +#endif
>> diff --git a/criu/include/protobuf-desc.h b/criu/include/protobuf-desc.h
>> index 6c76b49..43ac534 100644
>> --- a/criu/include/protobuf-desc.h
>> +++ b/criu/include/protobuf-desc.h
>> @@ -59,6 +59,10 @@ enum {
>> PB_BINFMT_MISC, /* 50 */
>> PB_TTY_DATA,
>> PB_AUTOFS,
>> + PB_REMOTE_IMAGE, /* Header for images sent from proxy to cache.*/
>> + PB_LOCAL_IMAGE, /* Header for reading/writing images from/to proxy or cache. */
>> + PB_LOCAL_IMAGE_REPLY, /* Header for reading/writing images reply. */
>> + PB_SNAPSHOT_ID, /* Contains a single id. Used for reading/writing ids from proxy or cache. */
>>
>> /* PB_AUTOGEN_STOP */
>>
>> diff --git a/criu/page-xfer.c b/criu/page-xfer.c
>> index 0da20e2..678ed85 100644
>> --- a/criu/page-xfer.c
>> +++ b/criu/page-xfer.c
>> @@ -19,6 +19,8 @@
>> #include "pstree.h"
>> #include "parasite-syscall.h"
>>
>> +#include "img-remote.h"
>> +
>> static int page_server_sk = -1;
>>
>> struct page_server_iov {
>> @@ -310,7 +312,8 @@ static int open_page_local_xfer(struct page_xfer *xfer, int fd_type, long id)
>>
>> xfer->parent = xmalloc(sizeof(*xfer->parent));
>> if (!xfer->parent) {
>> - close(pfd);
>> + if (!opts.remote)
>> + close(pfd);
>> return -1;
>> }
>>
>> @@ -319,10 +322,12 @@ static int open_page_local_xfer(struct page_xfer *xfer, int fd_type, long id)
>> pr_perror("No parent image found, though parent directory is set");
>> xfree(xfer->parent);
>> xfer->parent = NULL;
>> - close(pfd);
>> + if (!opts.remote)
>> + close(pfd);
>> goto out;
>> }
>> - close(pfd);
>> + if (!opts.remote)
>> + close(pfd);
>> }
>>
>> out:
>> @@ -459,9 +464,16 @@ int check_parent_local_xfer(int fd_type, int id)
>> struct stat st;
>> int ret, pfd;
>>
>> - pfd = openat(get_service_fd(IMG_FD_OFF), CR_PARENT_LINK, O_RDONLY);
>> - if (pfd < 0 && errno == ENOENT)
>> - return 0;
>> + if (opts.remote) {
>> + pfd = get_curr_parent_snapshot_id_idx();
>> + pr_err("Unable to get parent snapsgot id");
>> + if (pfd == -1)
>> + return -1;
>> + } else {
>> + pfd = openat(get_service_fd(IMG_FD_OFF), CR_PARENT_LINK, O_RDONLY);
>> + if (pfd < 0 && errno == ENOENT)
>> + return 0;
>> + }
>>
>> snprintf(path, sizeof(path), imgset_template[fd_type].fmt, id);
>> ret = fstatat(pfd, path, &st, 0);
>> @@ -523,6 +535,8 @@ int check_parent_page_xfer(int fd_type, long id)
>> {
>> if (opts.use_page_server)
>> return check_parent_server_xfer(fd_type, id);
>> + else if (opts.remote)
>> + return get_curr_parent_snapshot_id_idx() == -1 ? 0 : 1;
>> else
>> return check_parent_local_xfer(fd_type, id);
>> }
>> diff --git a/criu/pagemap.c b/criu/pagemap.c
>> index 227d561..81b31c5 100644
>> --- a/criu/pagemap.c
>> +++ b/criu/pagemap.c
>> @@ -11,6 +11,8 @@
>> #include "protobuf.h"
>> #include "images/pagemap.pb-c.h"
>>
>> +#include "img-remote.h"
>> +
>> #ifndef SEEK_DATA
>> #define SEEK_DATA 3
>> #define SEEK_HOLE 4
>> @@ -139,6 +141,8 @@ static int get_pagemap(struct page_read *pr, struct iovec *iov)
>> if (!pe->zero)
>> break;
>> put_pagemap(pr);
>> +
>> + pe = pr->pmes[pr->curr_pme];
>
> What is this hunk doing?
Both this and the bellow one I think are my errors.
I will correct them.
>
>> }
>>
>> pagemap2iovec(pe, iov);
>> @@ -160,7 +164,7 @@ static void skip_pagemap_pages(struct page_read *pr, unsigned long len)
>> return;
>>
>> pr_debug("\tpr%u Skip %lu bytes from page-dump\n", pr->id, len);
>> - if (!pr->pe->in_parent && !pr->pe->zero && !pr->pe->lazy)
>> + if (!pr->pe->in_parent && !pr->pe->zero && !pr->pe->lazy && !opts.remote)
>
> This place also needs explanation.
>
>> pr->pi_off += len;
>> pr->cvaddr += len;
>> }
>> @@ -268,12 +272,18 @@ static int read_pagemap_page(struct page_read *pr, unsigned long vaddr, int nr,
>> } else {
>> int fd = img_raw_fd(pr->pi);
>> off_t current_vaddr = lseek(fd, pr->pi_off, SEEK_SET);
>> + size_t curr = 0;
>>
>> pr_debug("\tpr%u Read page from self %lx/%"PRIx64"\n", pr->id, pr->cvaddr, current_vaddr);
>> - ret = read(fd, buf, len);
>> - if (ret != len) {
>> - pr_perror("Can't read mapping page %d", ret);
>> - return -1;
>> + while (1) {
>> + ret = read(fd, buf + curr, len - curr);
>> + if (ret < 1) {
>> + pr_perror("Can't read mapping page %d", ret);
>> + return -1;
>> + }
>> + curr += ret;
>> + if (curr == len)
>> + break;
>
> Please, send this as separate patch.
ok
>
>> }
>>
>> pr->pi_off += len;
>> @@ -345,9 +355,24 @@ static int try_open_parent(int dfd, int pid, struct page_read *pr, int pr_flags)
>> int pfd, ret;
>> struct page_read *parent = NULL;
>>
>> - pfd = openat(dfd, CR_PARENT_LINK, O_RDONLY);
>> - if (pfd < 0 && errno == ENOENT)
>> - goto out;
>> + if (opts.remote) {
>> + /* Note: we are replacing a real directory FD for a snapshot_id
>> + * index. Since we need the parent of the current snapshot_id,
>> + * we want the current snapshot_id index minus one. It is
>> + * possible that dfd is already a snapshot_id index. We test it
>> + * by comparing it to the service FD. When opening an image (see
>> + * do_open_image) we convert the snapshot_id index into a real
>> + * snapshot_id.
>> + */
>> + pfd = dfd == get_service_fd(IMG_FD_OFF) ?
>> + get_curr_snapshot_id_idx() - 1 : dfd - 1;
>> + if (pfd < 0)
>> + goto out;
>> + } else {
>> + pfd = openat(dfd, CR_PARENT_LINK, O_RDONLY);
>> + if (pfd < 0 && errno == ENOENT)
>> + goto out;
>> + }
>>
>> parent = xmalloc(sizeof(*parent));
>> if (!parent)
>> @@ -362,7 +387,8 @@ static int try_open_parent(int dfd, int pid, struct page_read *pr, int pr_flags)
>> parent = NULL;
>> }
>>
>> - close(pfd);
>> + if (!opts.remote)
>> + close(pfd);
>> out:
>> pr->parent = parent;
>> return 0;
>> @@ -370,7 +396,8 @@ out:
>> err_free:
>> xfree(parent);
>> err_cl:
>> - close(pfd);
>> + if (!opts.remote)
>> + close(pfd);
>> return -1;
>> }
>>
>> @@ -387,7 +414,11 @@ static int init_pagemaps(struct page_read *pr)
>> off_t fsize;
>> int nr_pmes, nr_realloc;
>>
>> - fsize = img_raw_size(pr->pmi);
>> + if (!opts.remote)
>> + fsize = img_raw_size(pr->pmi);
>> + else
>> + fsize = 1024; /*FIXME*/
>> +
>> if (fsize < 0)
>> return -1;
>>
>> diff --git a/criu/protobuf-desc.c b/criu/protobuf-desc.c
>> index 9352a76..c1850f9 100644
>> --- a/criu/protobuf-desc.c
>> +++ b/criu/protobuf-desc.c
>> @@ -64,6 +64,7 @@
>> #include "images/seccomp.pb-c.h"
>> #include "images/binfmt-misc.pb-c.h"
>> #include "images/autofs.pb-c.h"
>> +#include "images/remote-image.pb-c.h"
>>
>> struct cr_pb_message_desc cr_pb_descs[PB_MAX];
>>
>> diff --git a/images/Makefile b/images/Makefile
>> index cf50794..3753d62 100644
>> --- a/images/Makefile
>> +++ b/images/Makefile
>> @@ -60,6 +60,7 @@ proto-obj-y += binfmt-misc.o
>> proto-obj-y += time.o
>> proto-obj-y += sysctl.o
>> proto-obj-y += autofs.o
>> +proto-obj-y += remote-image.o
>>
>> CFLAGS += -iquote $(obj)/
>>
>> diff --git a/images/remote-image.proto b/images/remote-image.proto
>> new file mode 100644
>> index 0000000..1212627
>> --- /dev/null
>> +++ b/images/remote-image.proto
>> @@ -0,0 +1,20 @@
>> +message local_image_entry {
>> + required string name = 1;
>> + required string snapshot_id = 2;
>> + required uint32 open_mode = 3;
>> +}
>> +
>> +message remote_image_entry {
>> + required string name = 1;
>> + required string snapshot_id = 2;
>> + required uint32 open_mode = 3;
>> + required uint64 size = 4;
>> +}
>> +
>> +message local_image_reply_entry {
>> + required uint32 error = 1;
>> +}
>> +
>> +message snapshot_id_entry {
>> + required string snapshot_id = 1;
>> +}
>>
>
> That's the protocol. Can we have it separately (and the code too), please?
Sure.
I try to adjust the above comments, and resend the patches asap.
Thanks for the help :)
>
> -- Pavel
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