summaryrefslogtreecommitdiff
path: root/cmds-send.c
diff options
context:
space:
mode:
Diffstat (limited to 'cmds-send.c')
-rw-r--r--cmds-send.c744
1 files changed, 744 insertions, 0 deletions
diff --git a/cmds-send.c b/cmds-send.c
new file mode 100644
index 00000000..74d01287
--- /dev/null
+++ b/cmds-send.c
@@ -0,0 +1,744 @@
+/*
+ * Copyright (C) 2012 Alexander Block. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+
+#include "kerncompat.h"
+
+#include <unistd.h>
+#include <stdint.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <math.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <libgen.h>
+#include <mntent.h>
+#include <assert.h>
+#include <getopt.h>
+#include <uuid/uuid.h>
+#include <limits.h>
+
+#include "ctree.h"
+#include "ioctl.h"
+#include "commands.h"
+#include "list.h"
+#include "utils.h"
+
+#include "send.h"
+#include "send-utils.h"
+
+/*
+ * Default is 1 for historical reasons, changing may break scripts that expect
+ * the 'At subvol' message.
+ */
+static int g_verbose = 1;
+
+struct btrfs_send {
+ int send_fd;
+ int dump_fd;
+ int mnt_fd;
+
+ u64 *clone_sources;
+ u64 clone_sources_count;
+
+ char *root_path;
+ struct subvol_uuid_search sus;
+};
+
+static int get_root_id(struct btrfs_send *s, const char *path, u64 *root_id)
+{
+ struct subvol_info *si;
+
+ si = subvol_uuid_search(&s->sus, 0, NULL, 0, path,
+ subvol_search_by_path);
+ if (!si)
+ return -ENOENT;
+ *root_id = si->root_id;
+ free(si->path);
+ free(si);
+ return 0;
+}
+
+static struct subvol_info *get_parent(struct btrfs_send *s, u64 root_id)
+{
+ struct subvol_info *si_tmp;
+ struct subvol_info *si;
+
+ si_tmp = subvol_uuid_search(&s->sus, root_id, NULL, 0, NULL,
+ subvol_search_by_root_id);
+ if (!si_tmp)
+ return NULL;
+
+ si = subvol_uuid_search(&s->sus, 0, si_tmp->parent_uuid, 0, NULL,
+ subvol_search_by_uuid);
+ free(si_tmp->path);
+ free(si_tmp);
+ return si;
+}
+
+static int find_good_parent(struct btrfs_send *s, u64 root_id, u64 *found)
+{
+ int ret;
+ struct subvol_info *parent = NULL;
+ struct subvol_info *parent2 = NULL;
+ struct subvol_info *best_parent = NULL;
+ __s64 tmp;
+ u64 best_diff = (u64)-1;
+ int i;
+
+ parent = get_parent(s, root_id);
+ if (!parent) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ for (i = 0; i < s->clone_sources_count; i++) {
+ if (s->clone_sources[i] == parent->root_id) {
+ best_parent = parent;
+ parent = NULL;
+ goto out_found;
+ }
+ }
+
+ for (i = 0; i < s->clone_sources_count; i++) {
+ parent2 = get_parent(s, s->clone_sources[i]);
+ if (!parent2)
+ continue;
+ if (parent2->root_id != parent->root_id) {
+ free(parent2->path);
+ free(parent2);
+ parent2 = NULL;
+ continue;
+ }
+
+ free(parent2->path);
+ free(parent2);
+ parent2 = subvol_uuid_search(&s->sus, s->clone_sources[i], NULL,
+ 0, NULL, subvol_search_by_root_id);
+
+ if (!parent2) {
+ ret = -ENOENT;
+ goto out;
+ }
+ tmp = parent2->ctransid - parent->ctransid;
+ if (tmp < 0)
+ tmp *= -1;
+ if (tmp < best_diff) {
+ if (best_parent) {
+ free(best_parent->path);
+ free(best_parent);
+ }
+ best_parent = parent2;
+ parent2 = NULL;
+ best_diff = tmp;
+ } else {
+ free(parent2->path);
+ free(parent2);
+ parent2 = NULL;
+ }
+ }
+
+ if (!best_parent) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+out_found:
+ *found = best_parent->root_id;
+ ret = 0;
+
+out:
+ if (parent) {
+ free(parent->path);
+ free(parent);
+ }
+ if (best_parent) {
+ free(best_parent->path);
+ free(best_parent);
+ }
+ return ret;
+}
+
+static int add_clone_source(struct btrfs_send *s, u64 root_id)
+{
+ void *tmp;
+
+ tmp = s->clone_sources;
+ s->clone_sources = realloc(s->clone_sources,
+ sizeof(*s->clone_sources) * (s->clone_sources_count + 1));
+
+ if (!s->clone_sources) {
+ free(tmp);
+ return -ENOMEM;
+ }
+ s->clone_sources[s->clone_sources_count++] = root_id;
+
+ return 0;
+}
+
+static int write_buf(int fd, const void *buf, int size)
+{
+ int ret;
+ int pos = 0;
+
+ while (pos < size) {
+ ret = write(fd, (char*)buf + pos, size - pos);
+ if (ret < 0) {
+ ret = -errno;
+ error("failed to dump stream: %s", strerror(-ret));
+ goto out;
+ }
+ if (!ret) {
+ ret = -EIO;
+ error("failed to dump stream: %s", strerror(-ret));
+ goto out;
+ }
+ pos += ret;
+ }
+ ret = 0;
+
+out:
+ return ret;
+}
+
+static void *dump_thread(void *arg_)
+{
+ int ret;
+ struct btrfs_send *s = (struct btrfs_send*)arg_;
+ char buf[4096];
+ int readed;
+
+ while (1) {
+ readed = read(s->send_fd, buf, sizeof(buf));
+ if (readed < 0) {
+ ret = -errno;
+ error("failed to read stream from kernel: %s\n",
+ strerror(-ret));
+ goto out;
+ }
+ if (!readed) {
+ ret = 0;
+ goto out;
+ }
+ ret = write_buf(s->dump_fd, buf, readed);
+ if (ret < 0)
+ goto out;
+ }
+
+out:
+ if (ret < 0) {
+ exit(-ret);
+ }
+
+ return ERR_PTR(ret);
+}
+
+static int do_send(struct btrfs_send *send, u64 parent_root_id,
+ int is_first_subvol, int is_last_subvol, char *subvol,
+ u64 flags)
+{
+ int ret;
+ pthread_t t_read;
+ struct btrfs_ioctl_send_args io_send;
+ void *t_err = NULL;
+ int subvol_fd = -1;
+ int pipefd[2] = {-1, -1};
+
+ subvol_fd = openat(send->mnt_fd, subvol, O_RDONLY | O_NOATIME);
+ if (subvol_fd < 0) {
+ ret = -errno;
+ error("cannot open %s: %s", subvol, strerror(-ret));
+ goto out;
+ }
+
+ ret = pipe(pipefd);
+ if (ret < 0) {
+ ret = -errno;
+ error("pipe failed: %s", strerror(-ret));
+ goto out;
+ }
+
+ memset(&io_send, 0, sizeof(io_send));
+ io_send.send_fd = pipefd[1];
+ send->send_fd = pipefd[0];
+
+ if (!ret)
+ ret = pthread_create(&t_read, NULL, dump_thread,
+ send);
+ if (ret) {
+ ret = -ret;
+ error("thread setup failed: %s", strerror(-ret));
+ goto out;
+ }
+
+ io_send.flags = flags;
+ io_send.clone_sources = (__u64*)send->clone_sources;
+ io_send.clone_sources_count = send->clone_sources_count;
+ io_send.parent_root = parent_root_id;
+ if (!is_first_subvol)
+ io_send.flags |= BTRFS_SEND_FLAG_OMIT_STREAM_HEADER;
+ if (!is_last_subvol)
+ io_send.flags |= BTRFS_SEND_FLAG_OMIT_END_CMD;
+ ret = ioctl(subvol_fd, BTRFS_IOC_SEND, &io_send);
+ if (ret < 0) {
+ ret = -errno;
+ error("send ioctl failed with %d: %s", ret, strerror(-ret));
+ if (ret == -EINVAL && (!is_first_subvol || !is_last_subvol))
+ fprintf(stderr,
+ "Try upgrading your kernel or don't use -e.\n");
+ goto out;
+ }
+ if (g_verbose > 1)
+ fprintf(stderr, "BTRFS_IOC_SEND returned %d\n", ret);
+
+ if (g_verbose > 1)
+ fprintf(stderr, "joining genl thread\n");
+
+ close(pipefd[1]);
+ pipefd[1] = -1;
+
+ ret = pthread_join(t_read, &t_err);
+ if (ret) {
+ ret = -ret;
+ error("pthread_join failed: %s", strerror(-ret));
+ goto out;
+ }
+ if (t_err) {
+ ret = (long int)t_err;
+ error("failed to process send stream, ret=%ld (%s)",
+ (long int)t_err, strerror(-ret));
+ goto out;
+ }
+
+ ret = 0;
+
+out:
+ if (subvol_fd != -1)
+ close(subvol_fd);
+ if (pipefd[0] != -1)
+ close(pipefd[0]);
+ if (pipefd[1] != -1)
+ close(pipefd[1]);
+ return ret;
+}
+
+static int init_root_path(struct btrfs_send *s, const char *subvol)
+{
+ int ret = 0;
+
+ if (s->root_path)
+ goto out;
+
+ ret = find_mount_root(subvol, &s->root_path);
+ if (ret < 0) {
+ error("failed to determine mount point for %s: %s",
+ subvol, strerror(-ret));
+ ret = -EINVAL;
+ goto out;
+ }
+ if (ret > 0) {
+ error("%s doesn't belong to btrfs mount point", subvol);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ s->mnt_fd = open(s->root_path, O_RDONLY | O_NOATIME);
+ if (s->mnt_fd < 0) {
+ ret = -errno;
+ error("cannot open '%s': %s", s->root_path, strerror(-ret));
+ goto out;
+ }
+
+ ret = subvol_uuid_search_init(s->mnt_fd, &s->sus);
+ if (ret < 0) {
+ error("failed to initialize subvol search: %s",
+ strerror(-ret));
+ goto out;
+ }
+
+out:
+ return ret;
+
+}
+
+static int is_subvol_ro(struct btrfs_send *s, char *subvol)
+{
+ int ret;
+ u64 flags;
+ int fd = -1;
+
+ fd = openat(s->mnt_fd, subvol, O_RDONLY | O_NOATIME);
+ if (fd < 0) {
+ ret = -errno;
+ error("cannot open %s: %s", subvol, strerror(-ret));
+ goto out;
+ }
+
+ ret = ioctl(fd, BTRFS_IOC_SUBVOL_GETFLAGS, &flags);
+ if (ret < 0) {
+ ret = -errno;
+ error("failed to get flags for subvolume %s: %s",
+ subvol, strerror(-ret));
+ goto out;
+ }
+
+ if (flags & BTRFS_SUBVOL_RDONLY)
+ ret = 1;
+ else
+ ret = 0;
+
+out:
+ if (fd != -1)
+ close(fd);
+
+ return ret;
+}
+
+int cmd_send(int argc, char **argv)
+{
+ char *subvol = NULL;
+ int ret;
+ char outname[PATH_MAX];
+ struct btrfs_send send;
+ u32 i;
+ char *mount_root = NULL;
+ char *snapshot_parent = NULL;
+ u64 root_id = 0;
+ u64 parent_root_id = 0;
+ int full_send = 1;
+ int new_end_cmd_semantic = 0;
+ u64 send_flags = 0;
+
+ memset(&send, 0, sizeof(send));
+ send.dump_fd = fileno(stdout);
+ outname[0] = 0;
+
+ while (1) {
+ enum { GETOPT_VAL_SEND_NO_DATA = 256 };
+ static const struct option long_options[] = {
+ { "verbose", no_argument, NULL, 'v' },
+ { "quiet", no_argument, NULL, 'q' },
+ { "no-data", no_argument, NULL, GETOPT_VAL_SEND_NO_DATA }
+ };
+ int c = getopt_long(argc, argv, "vqec:f:i:p:", long_options, NULL);
+
+ if (c < 0)
+ break;
+
+ switch (c) {
+ case 'v':
+ g_verbose++;
+ break;
+ case 'q':
+ g_verbose = 0;
+ break;
+ case 'e':
+ new_end_cmd_semantic = 1;
+ break;
+ case 'c':
+ subvol = realpath(optarg, NULL);
+ if (!subvol) {
+ ret = -errno;
+ error("realpath %s failed: %s\n", optarg, strerror(-ret));
+ goto out;
+ }
+
+ ret = init_root_path(&send, subvol);
+ if (ret < 0)
+ goto out;
+
+ ret = get_root_id(&send,
+ subvol_strip_mountpoint(send.root_path, subvol),
+ &root_id);
+ if (ret < 0) {
+ error("cannot resolve rootid for %s", subvol);
+ goto out;
+ }
+
+ ret = is_subvol_ro(&send, subvol);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ ret = -EINVAL;
+ error("cloned subvolume %s is not read-only", subvol);
+ goto out;
+ }
+
+ ret = add_clone_source(&send, root_id);
+ if (ret < 0) {
+ error("cannot add clone source: %s", strerror(-ret));
+ goto out;
+ }
+ subvol_uuid_search_finit(&send.sus);
+ free(subvol);
+ subvol = NULL;
+ if (send.mnt_fd >= 0) {
+ close(send.mnt_fd);
+ send.mnt_fd = -1;
+ }
+ free(send.root_path);
+ send.root_path = NULL;
+ full_send = 0;
+ break;
+ case 'f':
+ if (arg_copy_path(outname, optarg, sizeof(outname))) {
+ error("output file path too long (%zu)", strlen(optarg));
+ ret = 1;
+ goto out;
+ }
+ break;
+ case 'p':
+ if (snapshot_parent) {
+ error("you cannot have more than one parent (-p)");
+ ret = 1;
+ goto out;
+ }
+ snapshot_parent = realpath(optarg, NULL);
+ if (!snapshot_parent) {
+ ret = -errno;
+ error("realpath %s failed: %s", optarg, strerror(-ret));
+ goto out;
+ }
+
+ ret = is_subvol_ro(&send, snapshot_parent);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ ret = -EINVAL;
+ error("parent subvolume %s is not read-only",
+ snapshot_parent);
+ goto out;
+ }
+
+ full_send = 0;
+ break;
+ case 'i':
+ error("option -i was removed, use -c instead");
+ ret = 1;
+ goto out;
+ case GETOPT_VAL_SEND_NO_DATA:
+ send_flags |= BTRFS_SEND_FLAG_NO_FILE_DATA;
+ break;
+ case '?':
+ default:
+ error("send arguments invalid");
+ ret = 1;
+ goto out;
+ }
+ }
+
+ if (check_argc_min(argc - optind, 1))
+ usage(cmd_send_usage);
+
+ if (outname[0]) {
+ send.dump_fd = creat(outname, 0600);
+ if (send.dump_fd == -1) {
+ ret = -errno;
+ error("cannot create '%s': %s", outname, strerror(-ret));
+ goto out;
+ }
+ }
+
+ if (isatty(send.dump_fd)) {
+ error(
+ "not dumping send stream into a terminal, redirect it into a file");
+ ret = 1;
+ goto out;
+ }
+
+ /* use first send subvol to determine mount_root */
+ subvol = argv[optind];
+
+ subvol = realpath(argv[optind], NULL);
+ if (!subvol) {
+ ret = -errno;
+ error("unable to resolve %s", argv[optind]);
+ goto out;
+ }
+
+ ret = init_root_path(&send, subvol);
+ if (ret < 0)
+ goto out;
+
+ if (snapshot_parent != NULL) {
+ ret = get_root_id(&send,
+ subvol_strip_mountpoint(send.root_path, snapshot_parent),
+ &parent_root_id);
+ if (ret < 0) {
+ error("could not resolve rootid for %s", snapshot_parent);
+ goto out;
+ }
+
+ ret = add_clone_source(&send, parent_root_id);
+ if (ret < 0) {
+ error("cannot add clone source: %s", strerror(-ret));
+ goto out;
+ }
+ }
+
+ for (i = optind; i < argc; i++) {
+ free(subvol);
+ subvol = realpath(argv[i], NULL);
+ if (!subvol) {
+ ret = -errno;
+ error("unable to resolve %s", argv[i]);
+ goto out;
+ }
+
+ ret = find_mount_root(subvol, &mount_root);
+ if (ret < 0) {
+ error("find_mount_root failed on %s: %s", subvol,
+ strerror(-ret));
+ goto out;
+ }
+ if (ret > 0) {
+ error("%s does not belong to btrfs mount point",
+ subvol);
+ ret = -EINVAL;
+ goto out;
+ }
+ if (strcmp(send.root_path, mount_root) != 0) {
+ ret = -EINVAL;
+ error("all subvolumes must be from the same filesystem");
+ goto out;
+ }
+ free(mount_root);
+
+ ret = is_subvol_ro(&send, subvol);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ ret = -EINVAL;
+ error("subvolume %s is not read-only", subvol);
+ goto out;
+ }
+ }
+
+ if ((send_flags & BTRFS_SEND_FLAG_NO_FILE_DATA) && g_verbose > 1)
+ if (g_verbose > 1)
+ fprintf(stderr, "Mode NO_FILE_DATA enabled\n");
+
+ for (i = optind; i < argc; i++) {
+ int is_first_subvol;
+ int is_last_subvol;
+
+ free(subvol);
+ subvol = argv[i];
+
+ if (g_verbose > 0)
+ fprintf(stderr, "At subvol %s\n", subvol);
+
+ subvol = realpath(subvol, NULL);
+ if (!subvol) {
+ ret = -errno;
+ error("realpath %s failed: %s", argv[i], strerror(-ret));
+ goto out;
+ }
+
+ if (!full_send && !parent_root_id) {
+ ret = find_good_parent(&send, root_id, &parent_root_id);
+ if (ret < 0) {
+ error("parent determination failed for %lld",
+ root_id);
+ goto out;
+ }
+ }
+
+ ret = is_subvol_ro(&send, subvol);
+ if (ret < 0)
+ goto out;
+ if (!ret) {
+ ret = -EINVAL;
+ error("subvolume %s is not read-only", subvol);
+ goto out;
+ }
+
+ if (new_end_cmd_semantic) {
+ /* require new kernel */
+ is_first_subvol = (i == optind);
+ is_last_subvol = (i == argc - 1);
+ } else {
+ /* be compatible to old and new kernel */
+ is_first_subvol = 1;
+ is_last_subvol = 1;
+ }
+ ret = do_send(&send, parent_root_id, is_first_subvol,
+ is_last_subvol, subvol, send_flags);
+ if (ret < 0)
+ goto out;
+
+ if (!full_send) {
+ /* done with this subvol, so add it to the clone sources */
+ ret = add_clone_source(&send, root_id);
+ if (ret < 0) {
+ error("cannot add clone source: %s", strerror(-ret));
+ goto out;
+ }
+ }
+
+ parent_root_id = 0;
+ }
+
+ ret = 0;
+
+out:
+ free(subvol);
+ free(snapshot_parent);
+ free(send.clone_sources);
+ if (send.mnt_fd >= 0)
+ close(send.mnt_fd);
+ free(send.root_path);
+ subvol_uuid_search_finit(&send.sus);
+ return !!ret;
+}
+
+const char * const cmd_send_usage[] = {
+ "btrfs send [-ve] [-p <parent>] [-c <clone-src>] [-f <outfile>] <subvol> [<subvol>...]",
+ "Send the subvolume(s) to stdout.",
+ "Sends the subvolume(s) specified by <subvol> to stdout.",
+ "<subvol> should be read-only here.",
+ "By default, this will send the whole subvolume. To do an incremental",
+ "send, use '-p <parent>'. If you want to allow btrfs to clone from",
+ "any additional local snapshots, use '-c <clone-src>' (multiple times",
+ "where applicable). You must not specify clone sources unless you",
+ "guarantee that these snapshots are exactly in the same state on both",
+ "sides, the sender and the receiver. It is allowed to omit the",
+ "'-p <parent>' option when '-c <clone-src>' options are given, in",
+ "which case 'btrfs send' will determine a suitable parent among the",
+ "clone sources itself.",
+ "\n",
+ "-e If sending multiple subvols at once, use the new",
+ " format and omit the end-cmd between the subvols.",
+ "-p <parent> Send an incremental stream from <parent> to",
+ " <subvol>.",
+ "-c <clone-src> Use this snapshot as a clone source for an ",
+ " incremental send (multiple allowed)",
+ "-f <outfile> Output is normally written to stdout. To write to",
+ " a file, use this option. An alternative would be to",
+ " use pipes.",
+ "--no-data send in NO_FILE_DATA mode, Note: the output stream",
+ " does not contain any file data and thus cannot be used",
+ " to transfer changes. This mode is faster and useful to",
+ " show the differences in metadata.",
+ "-v|--verbose enable verbose output to stderr, each occurrence of",
+ " this option increases verbosity",
+ "-q|--quiet suppress all messages, except errors",
+ NULL
+};