Hi Rory, Arne,
I think the problem is that currently mnt_fd in struct btrfs_receive
is used both as "mount root" and "directory in which the
subvolume/snapshot needs to be created".
Arne, does the following patch make sense? It uses Jan's
find_mount_root function. With this patch both Rory's tests seem to
work for me.
Thanks,
Alex.
diff --git a/cmds-receive.c b/cmds-receive.c
index a8be6fa..ed53326 100644
--- a/cmds-receive.c
+++ b/cmds-receive.c
@@ -52,11 +52,13 @@ static int g_verbose = 0;
struct btrfs_receive
{
int mnt_fd;
+ int dest_dir_fd;
int write_fd;
char *write_path;
char *root_path;
+ char *dest_dir_path; /* relative to root_path */
char *full_subvol_path;
struct subvol_info *cur_subvol;
@@ -150,8 +152,11 @@ static int process_subvol(const char *path, const
u8 *uuid, u64 ctransid,
r->cur_subvol = calloc(1, sizeof(*r->cur_subvol));
r->parent_subvol = NULL;
- r->cur_subvol->path = strdup(path);
- r->full_subvol_path = path_cat(r->root_path, path);
+ if (strlen(r->dest_dir_path) == 0)
+ r->cur_subvol->path = strdup(path);
+ else
+ r->cur_subvol->path = path_cat(r->dest_dir_path, path);
+ r->full_subvol_path = path_cat3(r->root_path, r->dest_dir_path, path);
fprintf(stderr, "At subvol %s\n", path);
@@ -167,7 +172,7 @@ static int process_subvol(const char *path, const
u8 *uuid, u64 ctransid,
memset(&args_v1, 0, sizeof(args_v1));
strcpy(args_v1.name, path);
- ret = ioctl(r->mnt_fd, BTRFS_IOC_SUBVOL_CREATE, &args_v1);
+ ret = ioctl(r->dest_dir_fd, BTRFS_IOC_SUBVOL_CREATE, &args_v1);
if (ret < 0) {
ret = -errno;
fprintf(stderr, "ERROR: creating subvolume %s failed. "
@@ -195,8 +200,11 @@ static int process_snapshot(const char *path,
const u8 *uuid, u64 ctransid,
r->cur_subvol = calloc(1, sizeof(*r->cur_subvol));
r->parent_subvol = NULL;
- r->cur_subvol->path = strdup(path);
- r->full_subvol_path = path_cat(r->root_path, path);
+ if (strlen(r->dest_dir_path) == 0)
+ r->cur_subvol->path = strdup(path);
+ else
+ r->cur_subvol->path = path_cat(r->dest_dir_path, path);
+ r->full_subvol_path = path_cat3(r->root_path, r->dest_dir_path, path);
fprintf(stderr, "At snapshot %s\n", path);
@@ -243,7 +251,7 @@ static int process_snapshot(const char *path,
const u8 *uuid, u64 ctransid,
goto out;
}
- ret = ioctl(r->mnt_fd, BTRFS_IOC_SNAP_CREATE_V2, &args_v2);
+ ret = ioctl(r->dest_dir_fd, BTRFS_IOC_SNAP_CREATE_V2, &args_v2);
close(args_v2.fd);
if (ret < 0) {
ret = -errno;
@@ -790,17 +798,44 @@ struct btrfs_send_ops send_ops = {
int do_receive(struct btrfs_receive *r, const char *tomnt, int r_fd)
{
int ret;
+ char *dest_dir_full_path;
int end = 0;
- r->root_path = strdup(tomnt);
- r->mnt_fd = open(tomnt, O_RDONLY | O_NOATIME);
+ dest_dir_full_path = realpath(tomnt, NULL);
+ if (!dest_dir_full_path) {
+ ret = -errno;
+ fprintf(stderr, "ERROR: realpath(%s) failed. %s\n", tomnt,
+ strerror(-ret));
+ goto out;
+ }
+ r->dest_dir_fd = open(tomnt, O_RDONLY | O_NOATIME);
+ if (r->dest_dir_fd < 0) {
+ ret = -errno;
+ fprintf(stderr, "ERROR: failed to open destination directory %s.
%s\n", tomnt,
+ strerror(-ret));
+ goto out;
+ }
+
+ ret = find_mount_root(tomnt, &r->root_path);
+ if (ret < 0) {
+ ret = -EINVAL;
+ fprintf(stderr, "ERROR: failed to determine mount point "
+ "for %s\n", tomnt);
+ goto out;
+ }
+ r->mnt_fd = open(r->root_path, O_RDONLY | O_NOATIME);
if (r->mnt_fd < 0) {
ret = -errno;
- fprintf(stderr, "ERROR: failed to open %s. %s\n", tomnt,
+ fprintf(stderr, "ERROR: failed to open %s. %s\n", r->root_path,
strerror(-ret));
goto out;
}
+ /* Find the destination dir relative to mount root */
+ r->dest_dir_path = dest_dir_full_path + strlen(r->root_path);
+ if (r->dest_dir_path[0] == '/')
+ r->dest_dir_path++;
+
ret = subvol_uuid_search_init(r->mnt_fd, &r->sus);
if (ret < 0)
return ret;
diff --git a/send-utils.h b/send-utils.h
index da407eb..a3e038b 100644
--- a/send-utils.h
+++ b/send-utils.h
@@ -65,5 +65,6 @@ void subvol_uuid_search_add(struct subvol_uuid_search *s,
char *path_cat(const char *p1, const char *p2);
char *path_cat3(const char *p1, const char *p2, const char *p3);
+int find_mount_root(const char *path, char **mount_root);
#endif /* SEND_UTILS_H_ */
On Tue, Oct 9, 2012 at 1:18 PM, Rory Campbell-Lange
<rory@xxxxxxxxxxxxxxxxxx> wrote:
> On 08/10/12, Arne Jansen (sensille@xxxxxxx) wrote:
>> On 10/08/12 18:30, Rory Campbell-Lange wrote:
>> > I can send snapshots to <volume>, but not <volume>/<dir>. Please advise
>> > if what I am doing is incorrect.
>
>> > Try and snap to /mnt/<subdir>
>> > root@orchard:/bkp# mkdir /mnt/snaps
>> > root@orchard:/bkp# btrfs send snaps/snap_081012_1715 | btrfs receive /mnt/snaps
>> > > At subvol snaps/snap_081012_1715
>> > > At subvol snap_081012_1715
>> > root@orchard:/bkp# btrfs send -p snaps/snap_081012_1715 \
>> > snaps/snap_081012_1716 | btrfs receive /mnt/snaps
>> > > At subvol snaps/snap_081012_1716
>> > > At snapshot snap_081012_1716
>> > > ERROR: open snaps/snap_081012_1715 failed. No such file or directory
>> > root@orchard:/bkp# ls /mnt/snaps
>> > > snap_081012_1715
>>
>> The target has to be a subvol also. But interestingly enough, it also
>> fails for a subvol. The base send works, the incremental fails, because
>> btrfs receive can't find snaps/snap_081012_1715. If you give /mnt/snaps
>> as the target for the base and just /mnt for the incremental, it works.
>> There's clearly something broken there...
>
> Actually, this does work:
>
> root@orchard:~# mkfs.btrfs /dev/sdb1
> ...snip...
> > Btrfs v0.20-rc1-37-g91d9eec
> root@orchard:/bkp# ls
> > snaps subvol
> root@orchard:/bkp# mount /dev/sdb1 /mnt
> root@orchard:/bkp# btrfs subvolume create /mnt/subvol
> > Create subvolume '/mnt/subvol'
> root@orchard:/bkp# btrfs send snaps/snap_081012_1715 | btrfs receive /mnt/subvol
> > At subvol snaps/snap_081012_1715
> > At subvol snap_081012_1715
> root@orchard:/bkp# btrfs send -p snaps/snap_081012_1715 \
> snaps/snap_081012_1716 | btrfs receive /mnt/subvol
> > At subvol snaps/snap_081012_1716
> > At snapshot snap_081012_1716
>
> It certainly seems to work if the receive target is a subvolume other
> than the implicit subvolume at the root of the mount point.
>
> So one can only btrfs receive to a subvolume, which makes sense, and is
> I believe the reason one cannot 'btrfs receive to a subdirectory' as set
> out in the subject of my original email.
>
> Are there any other problem cases you can see, Arne?
>
> Regards
> Rory
>
> --
> Rory Campbell-Lange
> rory@xxxxxxxxxxxxxxxxxx
> --
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