Commit 65db0e5a by S.Çağlar Onur Committed by Stéphane Graber

use btrfs snapshot feature to restore snapshots

fixes #131 changes since v1; * uses btrfs snapshot feature only if src and dest are on same fs Signed-off-by: 's avatarS.Çağlar Onur <caglar@10ur.org> Acked-by: 's avatarSerge E. Hallyn <serge.hallyn@ubuntu.com>
parent 73d28d42
......@@ -1336,6 +1336,57 @@ static int btrfs_subvolume_create(const char *path)
return ret;
}
#define BTRFS_FSID_SIZE 16
struct btrfs_ioctl_fs_info_args {
unsigned long long max_id;
unsigned long long num_devices;
char fsid[BTRFS_FSID_SIZE];
unsigned long long reserved[124];
};
#define BTRFS_IOC_FS_INFO _IOR(BTRFS_IOCTL_MAGIC, 31, \
struct btrfs_ioctl_fs_info_args)
static int btrfs_same_fs(const char *orig, const char *new) {
int fd_orig = -1, fd_new = -1, ret = -1;
struct btrfs_ioctl_fs_info_args orig_args, new_args;
fd_orig = open(orig, O_RDONLY);
if (fd_orig < 0) {
SYSERROR("Error opening original rootfs %s", orig);
goto out;
}
ret = ioctl(fd_orig, BTRFS_IOC_FS_INFO, &orig_args);
if (ret < 0) {
SYSERROR("BTRFS_IOC_FS_INFO %s", orig);
goto out;
}
fd_new = open(new, O_RDONLY);
if (fd_new < 0) {
SYSERROR("Error opening new container dir %s", new);
err = -1;
goto out;
}
ret = ioctl(fd_new, BTRFS_IOC_FS_INFO, &new_args);
if (ret < 0) {
SYSERROR("BTRFS_IOC_FS_INFO %s", new);
goto out;
}
if (strncmp(orig_args.fsid, new_args.fsid, BTRFS_FSID_SIZE) != 0) {
ret = -1;
goto out;
}
ret = 0;
out:
if (fd_new != -1)
close(fd_new);
if (fd_orig != -1)
close(fd_orig);
return ret;
}
static int btrfs_snapshot(const char *orig, const char *new)
{
int fd = -1, fddst = -1, ret = -1;
......@@ -2587,9 +2638,7 @@ struct bdev *bdev_copy(struct lxc_container *c0, const char *cname,
if (new->ops->clone_paths(orig, new, oldname, cname, oldpath, lxcpath,
snap, newsize, c0->lxc_conf) < 0) {
ERROR("failed getting pathnames for cloned storage: %s", src);
bdev_put(orig);
bdev_put(new);
return NULL;
goto err;
}
if (am_unpriv() && chown_mapped_root(new->src, c0->lxc_conf) < 0)
......@@ -2598,12 +2647,33 @@ struct bdev *bdev_copy(struct lxc_container *c0, const char *cname,
if (snap)
return new;
/*
* https://github.com/lxc/lxc/issues/131
* Use btrfs snapshot feature instead of rsync to restore if both orig and new are btrfs
*/
if (bdevtype &&
strcmp(orig->type, "btrfs") == 0 && strcmp(new->type, "btrfs") == 0 &&
btrfs_same_fs(orig->dest, new->dest) == 0) {
if (btrfs_destroy(new) < 0) {
ERROR("Error destroying %s subvolume", new->dest);
goto err;
}
if (mkdir_p(new->dest, 0755) < 0) {
ERROR("Error creating %s directory", new->dest);
goto err;
}
if (btrfs_snapshot(orig->dest, new->dest) < 0) {
ERROR("Error restoring %s to %s", orig->dest, new->dest);
goto err;
}
bdev_put(orig);
return new;
}
pid = fork();
if (pid < 0) {
SYSERROR("fork");
bdev_put(orig);
bdev_put(new);
return NULL;
goto err;
}
if (pid > 0) {
......@@ -2624,6 +2694,11 @@ struct bdev *bdev_copy(struct lxc_container *c0, const char *cname,
ret = rsync_rootfs(&data);
exit(ret == 0 ? 0 : 1);
err:
bdev_put(orig);
bdev_put(new);
return NULL;
}
static struct bdev * do_bdev_create(const char *dest, const char *type,
......
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