2 * Copyright (C) 2012 Alexander Block. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
20 #include "kerncompat.h"
29 #include <sys/types.h>
30 #include <sys/ioctl.h>
35 #include <uuid/uuid.h>
45 #include "send-utils.h"
47 #define SEND_BUFFER_SIZE (64 * 1024)
50 * Default is 1 for historical reasons, changing may break scripts that expect
51 * the 'At subvol' message.
53 static int g_verbose = 1;
61 u64 clone_sources_count;
64 struct subvol_uuid_search sus;
67 static int get_root_id(struct btrfs_send *s, const char *path, u64 *root_id)
69 struct subvol_info *si;
71 si = subvol_uuid_search(&s->sus, 0, NULL, 0, path,
72 subvol_search_by_path);
75 *root_id = si->root_id;
81 static struct subvol_info *get_parent(struct btrfs_send *s, u64 root_id)
83 struct subvol_info *si_tmp;
84 struct subvol_info *si;
86 si_tmp = subvol_uuid_search(&s->sus, root_id, NULL, 0, NULL,
87 subvol_search_by_root_id);
91 si = subvol_uuid_search(&s->sus, 0, si_tmp->parent_uuid, 0, NULL,
92 subvol_search_by_uuid);
98 static int find_good_parent(struct btrfs_send *s, u64 root_id, u64 *found)
101 struct subvol_info *parent = NULL;
102 struct subvol_info *parent2 = NULL;
103 struct subvol_info *best_parent = NULL;
105 u64 best_diff = (u64)-1;
108 parent = get_parent(s, root_id);
114 for (i = 0; i < s->clone_sources_count; i++) {
115 if (s->clone_sources[i] == parent->root_id) {
116 best_parent = parent;
122 for (i = 0; i < s->clone_sources_count; i++) {
123 parent2 = get_parent(s, s->clone_sources[i]);
126 if (parent2->root_id != parent->root_id) {
135 parent2 = subvol_uuid_search(&s->sus, s->clone_sources[i], NULL,
136 0, NULL, subvol_search_by_root_id);
142 tmp = parent2->ctransid - parent->ctransid;
145 if (tmp < best_diff) {
147 free(best_parent->path);
150 best_parent = parent2;
166 *found = best_parent->root_id;
175 free(best_parent->path);
181 static int add_clone_source(struct btrfs_send *s, u64 root_id)
185 tmp = s->clone_sources;
186 s->clone_sources = realloc(s->clone_sources,
187 sizeof(*s->clone_sources) * (s->clone_sources_count + 1));
189 if (!s->clone_sources) {
193 s->clone_sources[s->clone_sources_count++] = root_id;
198 static int write_buf(int fd, const void *buf, int size)
204 ret = write(fd, (char*)buf + pos, size - pos);
207 error("failed to dump stream: %s", strerror(-ret));
212 error("failed to dump stream: %s", strerror(-ret));
223 static void *dump_thread(void *arg_)
226 struct btrfs_send *s = (struct btrfs_send*)arg_;
227 char buf[SEND_BUFFER_SIZE];
232 rbytes = read(s->send_fd, buf, sizeof(buf));
235 error("failed to read stream from kernel: %s\n",
243 ret = write_buf(s->dump_fd, buf, rbytes);
256 static int do_send(struct btrfs_send *send, u64 parent_root_id,
257 int is_first_subvol, int is_last_subvol, const char *subvol,
262 struct btrfs_ioctl_send_args io_send;
265 int pipefd[2] = {-1, -1};
267 subvol_fd = openat(send->mnt_fd, subvol, O_RDONLY | O_NOATIME);
270 error("cannot open %s: %s", subvol, strerror(-ret));
277 error("pipe failed: %s", strerror(-ret));
281 memset(&io_send, 0, sizeof(io_send));
282 io_send.send_fd = pipefd[1];
283 send->send_fd = pipefd[0];
286 ret = pthread_create(&t_read, NULL, dump_thread,
290 error("thread setup failed: %s", strerror(-ret));
294 io_send.flags = flags;
295 io_send.clone_sources = (__u64*)send->clone_sources;
296 io_send.clone_sources_count = send->clone_sources_count;
297 io_send.parent_root = parent_root_id;
298 if (!is_first_subvol)
299 io_send.flags |= BTRFS_SEND_FLAG_OMIT_STREAM_HEADER;
301 io_send.flags |= BTRFS_SEND_FLAG_OMIT_END_CMD;
302 ret = ioctl(subvol_fd, BTRFS_IOC_SEND, &io_send);
305 error("send ioctl failed with %d: %s", ret, strerror(-ret));
306 if (ret == -EINVAL && (!is_first_subvol || !is_last_subvol))
308 "Try upgrading your kernel or don't use -e.\n");
312 fprintf(stderr, "BTRFS_IOC_SEND returned %d\n", ret);
315 fprintf(stderr, "joining genl thread\n");
320 ret = pthread_join(t_read, &t_err);
323 error("pthread_join failed: %s", strerror(-ret));
327 ret = (long int)t_err;
328 error("failed to process send stream, ret=%ld (%s)",
329 (long int)t_err, strerror(-ret));
345 static int init_root_path(struct btrfs_send *s, const char *subvol)
352 ret = find_mount_root(subvol, &s->root_path);
354 error("failed to determine mount point for %s: %s",
355 subvol, strerror(-ret));
360 error("%s doesn't belong to btrfs mount point", subvol);
365 s->mnt_fd = open(s->root_path, O_RDONLY | O_NOATIME);
368 error("cannot open '%s': %s", s->root_path, strerror(-ret));
372 ret = subvol_uuid_search_init(s->mnt_fd, &s->sus);
374 error("failed to initialize subvol search: %s",
384 static int is_subvol_ro(struct btrfs_send *s, const char *subvol)
390 fd = openat(s->mnt_fd, subvol, O_RDONLY | O_NOATIME);
393 error("cannot open %s: %s", subvol, strerror(-ret));
397 ret = ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags);
400 error("failed to get flags for subvolume %s: %s",
401 subvol, strerror(-ret));
405 if (flags & BTRFS_SUBVOL_RDONLY)
417 int cmd_send(int argc, char **argv)
421 char outname[PATH_MAX];
422 struct btrfs_send send;
424 char *mount_root = NULL;
425 char *snapshot_parent = NULL;
427 u64 parent_root_id = 0;
429 int new_end_cmd_semantic = 0;
432 memset(&send, 0, sizeof(send));
433 send.dump_fd = fileno(stdout);
437 enum { GETOPT_VAL_SEND_NO_DATA = 256 };
438 static const struct option long_options[] = {
439 { "verbose", no_argument, NULL, 'v' },
440 { "quiet", no_argument, NULL, 'q' },
441 { "no-data", no_argument, NULL, GETOPT_VAL_SEND_NO_DATA }
443 int c = getopt_long(argc, argv, "vqec:f:i:p:", long_options, NULL);
456 new_end_cmd_semantic = 1;
459 subvol = realpath(optarg, NULL);
462 error("realpath %s failed: %s\n", optarg, strerror(-ret));
466 ret = init_root_path(&send, subvol);
470 ret = get_root_id(&send,
471 subvol_strip_mountpoint(send.root_path, subvol),
474 error("cannot resolve rootid for %s", subvol);
478 ret = is_subvol_ro(&send, subvol);
483 error("cloned subvolume %s is not read-only", subvol);
487 ret = add_clone_source(&send, root_id);
489 error("cannot add clone source: %s", strerror(-ret));
492 subvol_uuid_search_finit(&send.sus);
495 if (send.mnt_fd >= 0) {
499 free(send.root_path);
500 send.root_path = NULL;
504 if (arg_copy_path(outname, optarg, sizeof(outname))) {
505 error("output file path too long (%zu)", strlen(optarg));
511 if (snapshot_parent) {
512 error("you cannot have more than one parent (-p)");
516 snapshot_parent = realpath(optarg, NULL);
517 if (!snapshot_parent) {
519 error("realpath %s failed: %s", optarg, strerror(-ret));
523 ret = is_subvol_ro(&send, snapshot_parent);
528 error("parent subvolume %s is not read-only",
536 error("option -i was removed, use -c instead");
539 case GETOPT_VAL_SEND_NO_DATA:
540 send_flags |= BTRFS_SEND_FLAG_NO_FILE_DATA;
544 error("send arguments invalid");
550 if (check_argc_min(argc - optind, 1))
551 usage(cmd_send_usage);
554 send.dump_fd = creat(outname, 0600);
555 if (send.dump_fd == -1) {
557 error("cannot create '%s': %s", outname, strerror(-ret));
562 if (isatty(send.dump_fd)) {
564 "not dumping send stream into a terminal, redirect it into a file");
569 /* use first send subvol to determine mount_root */
570 subvol = realpath(argv[optind], NULL);
573 error("unable to resolve %s", argv[optind]);
577 ret = init_root_path(&send, subvol);
581 if (snapshot_parent != NULL) {
582 ret = get_root_id(&send,
583 subvol_strip_mountpoint(send.root_path, snapshot_parent),
586 error("could not resolve rootid for %s", snapshot_parent);
590 ret = add_clone_source(&send, parent_root_id);
592 error("cannot add clone source: %s", strerror(-ret));
597 for (i = optind; i < argc; i++) {
599 subvol = realpath(argv[i], NULL);
602 error("unable to resolve %s", argv[i]);
606 ret = find_mount_root(subvol, &mount_root);
608 error("find_mount_root failed on %s: %s", subvol,
613 error("%s does not belong to btrfs mount point",
618 if (strcmp(send.root_path, mount_root) != 0) {
620 error("all subvolumes must be from the same filesystem");
625 ret = is_subvol_ro(&send, subvol);
630 error("subvolume %s is not read-only", subvol);
635 if ((send_flags & BTRFS_SEND_FLAG_NO_FILE_DATA) && g_verbose > 1)
637 fprintf(stderr, "Mode NO_FILE_DATA enabled\n");
639 for (i = optind; i < argc; i++) {
647 fprintf(stderr, "At subvol %s\n", subvol);
649 subvol = realpath(subvol, NULL);
652 error("realpath %s failed: %s", argv[i], strerror(-ret));
656 if (!full_send && root_id) {
657 ret = find_good_parent(&send, root_id, &parent_root_id);
659 error("parent determination failed for %lld",
665 if (new_end_cmd_semantic) {
666 /* require new kernel */
667 is_first_subvol = (i == optind);
668 is_last_subvol = (i == argc - 1);
670 /* be compatible to old and new kernel */
674 ret = do_send(&send, parent_root_id, is_first_subvol,
675 is_last_subvol, subvol, send_flags);
679 if (!full_send && root_id) {
680 /* done with this subvol, so add it to the clone sources */
681 ret = add_clone_source(&send, root_id);
683 error("cannot add clone source: %s", strerror(-ret));
693 free(snapshot_parent);
694 free(send.clone_sources);
695 if (send.mnt_fd >= 0)
697 free(send.root_path);
698 subvol_uuid_search_finit(&send.sus);
702 const char * const cmd_send_usage[] = {
703 "btrfs send [-ve] [-p <parent>] [-c <clone-src>] [-f <outfile>] <subvol> [<subvol>...]",
704 "Send the subvolume(s) to stdout.",
705 "Sends the subvolume(s) specified by <subvol> to stdout.",
706 "<subvol> should be read-only here.",
707 "By default, this will send the whole subvolume. To do an incremental",
708 "send, use '-p <parent>'. If you want to allow btrfs to clone from",
709 "any additional local snapshots, use '-c <clone-src>' (multiple times",
710 "where applicable). You must not specify clone sources unless you",
711 "guarantee that these snapshots are exactly in the same state on both",
712 "sides, the sender and the receiver. It is allowed to omit the",
713 "'-p <parent>' option when '-c <clone-src>' options are given, in",
714 "which case 'btrfs send' will determine a suitable parent among the",
715 "clone sources itself.",
717 "-e If sending multiple subvols at once, use the new",
718 " format and omit the end-cmd between the subvols.",
719 "-p <parent> Send an incremental stream from <parent> to",
721 "-c <clone-src> Use this snapshot as a clone source for an ",
722 " incremental send (multiple allowed)",
723 "-f <outfile> Output is normally written to stdout. To write to",
724 " a file, use this option. An alternative would be to",
726 "--no-data send in NO_FILE_DATA mode, Note: the output stream",
727 " does not contain any file data and thus cannot be used",
728 " to transfer changes. This mode is faster and useful to",
729 " show the differences in metadata.",
730 "-v|--verbose enable verbose output to stderr, each occurrence of",
731 " this option increases verbosity",
732 "-q|--quiet suppress all messages, except errors",