This patch implements functionality for following ioctl:
BTRFS_IOC_DEFAULT_SUBVOL - Setting a default subvolume
Set a default subvolume for a btrfs filesystem. The third
ioctl's argument is a '__u64' (unsigned long long) which
represents the id of a subvolume that is to be set as
the default.
BTRFS_IOC_GET_SUBVOL_ROOTREF - Getting tree and directory id of subvolumes
Read tree and directory id of subvolumes from a btrfs
filesystem. The tree and directory id's are returned in the
ioctl's third argument which represents a pointer to a
following type:
struct btrfs_ioctl_get_subvol_rootref_args {
/* in/out, minimum id of rootref's treeid to be searched */
__u64 min_treeid;
/* out */
struct {
__u64 treeid;
__u64 dirid;
} rootref[BTRFS_MAX_ROOTREF_BUFFER_NUM];
/* out, number of found items */
__u8 num_items;
__u8 align[7];
};
Before calling this ioctl, 'min_treeid' field should be filled
with value that represent the minimum value for the tree id.
Implementation notes:
Ioctl BTRFS_IOC_GET_SUBVOL_ROOTREF uses the above mentioned structure
type as third argument. That is the reason why a aproppriate thunk
structure definition is added in file 'syscall_types.h'.
Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
Tested-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200823195014.116226-7-Filip.Bozuta@syrmia.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
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