| Message ID | 1394207319-13252-1-git-send-email-Anand.Jain@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Any comments on this set of patches ? Thanks, Anand On 07/03/2014 23:48, Anand Jain wrote: > The intended usage of total_devices and num_devices > should be recorded in the comments so that these > two counters can be used correctly as originally > intended. > > As of now there appears to be slight deviations/bugs > from the original intention, the bugs are apparent > that num_devices does not count seed devices where > as total_devices does, but total_devices does not > count the replacing devices where as num_devices does. > > So in this situation the ioctl(BTRFS_IOC_DEVICES_READY) > will fails when there is seed FS. Next, applications > using ioctl(BTRFS_IOC_FS_INFO) and ioctl(BTRFS_IOC_DEV_INFO) > in conjunction to allocate the slots will also fail > as former depend on the num_devices where as latter > would match total_devices (except when replace is running). > > This patch will help have the clarity on usage > of these two counter so that bugs related to this can > be fixed. > > Signed-off-by: Anand Jain <Anand.Jain@oracle.com> > --- > v2: edit commit > > fs/btrfs/volumes.h | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h > index 91b7596..99c71aa 100644 > --- a/fs/btrfs/volumes.h > +++ b/fs/btrfs/volumes.h > @@ -121,12 +121,18 @@ struct btrfs_fs_devices { > /* the device with this id has the most recent copy of the super */ > u64 latest_devid; > u64 latest_trans; > + /* num_devices contains run time count of devices which are part > + * of this FSID. (the FS devices + replacing devices + ? > + */ > u64 num_devices; > u64 open_devices; > u64 rw_devices; > u64 missing_devices; > u64 total_rw_bytes; > u64 num_can_discard; > + /* total_devices contains static recorded count of device which > + * are part of this FSID. (the FS devices + seed devices + ? > + */ > u64 total_devices; > struct block_device *latest_bdev; > > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 91b7596..99c71aa 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -121,12 +121,18 @@ struct btrfs_fs_devices { /* the device with this id has the most recent copy of the super */ u64 latest_devid; u64 latest_trans; + /* num_devices contains run time count of devices which are part + * of this FSID. (the FS devices + replacing devices + ? + */ u64 num_devices; u64 open_devices; u64 rw_devices; u64 missing_devices; u64 total_rw_bytes; u64 num_can_discard; + /* total_devices contains static recorded count of device which + * are part of this FSID. (the FS devices + seed devices + ? + */ u64 total_devices; struct block_device *latest_bdev;
The intended usage of total_devices and num_devices should be recorded in the comments so that these two counters can be used correctly as originally intended. As of now there appears to be slight deviations/bugs from the original intention, the bugs are apparent that num_devices does not count seed devices where as total_devices does, but total_devices does not count the replacing devices where as num_devices does. So in this situation the ioctl(BTRFS_IOC_DEVICES_READY) will fails when there is seed FS. Next, applications using ioctl(BTRFS_IOC_FS_INFO) and ioctl(BTRFS_IOC_DEV_INFO) in conjunction to allocate the slots will also fail as former depend on the num_devices where as latter would match total_devices (except when replace is running). This patch will help have the clarity on usage of these two counter so that bugs related to this can be fixed. Signed-off-by: Anand Jain <Anand.Jain@oracle.com> --- v2: edit commit fs/btrfs/volumes.h | 6 ++++++ 1 file changed, 6 insertions(+)