On Wednesday, 15 December, 2010, Li Zefan wrote:
> Goffredo Baroncelli wrote:
> > On Wednesday, 15 December, 2010, Li Zefan wrote:
> >> h4) objectid asis, type asis, offset++ -> we should get the correct
result.
> >
> > This fix the problem of the "missing subvolume". But for the other case
> > (searching for more than one type) the problem still here.
> >
>
> I don't think so. And the above "h4" has showed how we search for more
> than one type.
>
> The generic userland code for next search is:
>
> /* this is in essence the same as how we advance key in kernel code */
> if (sk->min_offset < (u64)-1 && sk->min_offset < sk->max_offset)
> sk->min_offset++;
> else if (sk->min_type < (u8)-1 && sk->min_type < sk->max_type) {
> sk->min_offset = 0;
> sk->min_type++;
> } else if (sk->min_objectid < (u64)-1 && sk->min_objectid < sk-
>max_objectid){
> sk->min_offset = 0;
> sk->min_type = 0;
Sorry but if you reset the sk->min_type to 0, this means that the min_type
lost its purpose (act as lover bound of the acceptance criteria).
> sk->min_objectid++;
> } else
> break;
>
> ioctl(...);
>
> for (i = 0; i < nr_items; i++) {
> if (!filter(items[i]))
> continue;
So you are suggesting: "Move all tree items from kernel to user space and
filter it in userspace ?". This mean a lot of un-needed kernel-space <->
userspace transition...
Sorry I don't understand if we are talking about a workaround or a solution.
> /* process this item */
> ...
> }
>
> >> because the current ioctl uses min_{x,y,z} and max_{x,y,z} as start_key
and
> >> end_key, and it returns all keys that falls in [start_key, end_key].
> >>
> >> So this btrfs-progs patch should fix missing subvolumes in the output of
> >> "subvolume list":
> >>
> >> diff --git a/btrfs-list.c b/btrfs-list.c
> >> index 93766a8..1b9ea45 100644
> >> --- a/btrfs-list.c
> >> +++ b/btrfs-list.c
> >> @@ -620,7 +620,10 @@ int list_subvols(int fd)
> >> /* this iteration is done, step forward one root for the
> > next
> >> * ioctl
> >> */
> >> - if (sk->min_objectid < (u64)-1) {
> >> + if (sk->min_type < BTRFS_ROOT_BACKREF_KEY) {
> >> + sk->min_type = BTRFS_ROOT_BACKREF_KEY;
> >> + sk->min_offset = 0;
> >> + } else if (sk->min_objectid < (u64)-1) {
> >> sk->min_objectid++;
> >> sk->min_type = BTRFS_ROOT_BACKREF_KEY;
> >> sk->min_offset = 0;
> >>
> >
> >
> --
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