110 lines
3 KiB
C
110 lines
3 KiB
C
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/*
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btrfs receive currently mandates that incremental receives can only be performed on a parent subvolume
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that was also received. This means you cannot apply it to (snapshotted) subvolumes you still have on disk,
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as they were not received themselves.
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This small utility allows you to set the received_uuid of a subvolume, tricking btrfs receive into using it.
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found on btrfs mailing list
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read the discussion here: http://comments.gmane.org/gmane.comp.file-systems.btrfs/21922
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*/
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#define _GNU_SOURCE
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#include <unistd.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <uuid/uuid.h>
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#include <sys/ioctl.h>
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#include "ctree.h"
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#include "ioctl.h"
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#include "send-utils.h"
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#define CLEAR(var) memset(&var, 0, sizeof(var))
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int main(int argc, char **argv) {
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int ret, fd;
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struct subvol_uuid_search sus;
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struct btrfs_ioctl_received_subvol_args rs_args;
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struct subvol_info *si;
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char uuidbuf[37], parent_uuidbuf[37], received_uuidbuf[37];
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if (argc != 3 && argc != 4) {
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printf("usage: btrfs-set-received-uuid btrfs-mountpoint src-subvolume-path-relative-to-mountpoint [dest-absolute-subvolume-path]\n");
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exit(1);
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}
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printf("opening srcmnt %s\n", argv[1]);
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fd = open(argv[1], O_RDONLY | O_NOATIME);
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if (fd < 0) {
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printf("failed to open srcmnt %s! %s\n", argv[1], strerror(errno));
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exit(2);
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}
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puts("initializing sub search");
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CLEAR(sus);
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ret = subvol_uuid_search_init(fd, &sus);
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if (ret < 0) {
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printf("failed to initialize sub search! %s\n", strerror(-ret));
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exit(3);
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}
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printf("searching srcsub %s\n", argv[2]);
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si = subvol_uuid_search(&sus, 0, NULL, 0, argv[2], subvol_search_by_path);
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if (!si) {
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puts("srcsub not found!");
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exit(4);
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}
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uuid_unparse(si->uuid, uuidbuf);
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uuid_unparse(si->parent_uuid, parent_uuidbuf);
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uuid_unparse(si->received_uuid, received_uuidbuf);
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printf("\nsrcsub found:\n"
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" uuid=%s\n"
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" parent_uuid=%s\n"
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"received_uuid=%s\n"
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"ctransid=%Lu otransid=%Lu stransid=%Lu rtransid=%Lu\n\n",
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uuidbuf, parent_uuidbuf, received_uuidbuf,
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(unsigned long long)(si->ctransid),
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(unsigned long long)(si->otransid),
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(unsigned long long)(si->stransid),
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(unsigned long long)(si->rtransid));
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if (argc == 3)
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goto done;
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printf("opening dst subvol %s\n", argv[3]);
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fd = open(argv[3], O_RDONLY | O_NOATIME);
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if (fd < 0) {
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printf("failed to open dst subvol %s. %s\n", argv[3], strerror(errno));
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exit(5);
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}
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printf("\nhere we go with BTRFS_IOC_SET_RECEIVED_SUBVOL:\n"
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"dstsub.received_uuid = srcsub.uuid == %s\n"
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"dstsub.stransid = srcsub.ctransid == %Lu\n\n",
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uuidbuf, (unsigned long long)(si->ctransid));
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CLEAR(rs_args);
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memcpy(rs_args.uuid, si->uuid, BTRFS_UUID_SIZE);
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rs_args.stransid = si->ctransid;
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ret = ioctl(fd, BTRFS_IOC_SET_RECEIVED_SUBVOL, &rs_args);
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if (ret < 0) {
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printf("BTRFS_IOC_SET_RECEIVED_SUBVOL failed: %s", strerror(-ret));
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exit(6);
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}
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done:
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printf("done.\n");
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exit(0);
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}
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