From 12907fc79818a62a2478f84f7795afa774bf7f9c Mon Sep 17 00:00:00 2001 From: David Sterba Date: Sat, 10 Oct 2015 17:16:50 +0200 Subject: btrfs: extend balance filter limit to take minimum and maximum The 'limit' filter is underdesigned, it should have been a range for [min,max], with some relaxed semantics when one of the bounds is missing. Besides that, using a full u64 for a single value is a waste of bytes. Let's fix both by extending the use of the u64 bytes for the [min,max] range. This can be done in a backward compatible way, the range will be interpreted only if the appropriate flag is set (BTRFS_BALANCE_ARGS_LIMIT_RANGE). Signed-off-by: David Sterba Signed-off-by: Chris Mason --- include/uapi/linux/btrfs.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index b6dec05c7196..11f13108b78b 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -217,7 +217,18 @@ struct btrfs_balance_args { __u64 flags; - __u64 limit; /* limit number of processed chunks */ + /* + * BTRFS_BALANCE_ARGS_LIMIT with value 'limit' + * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum + * and maximum + */ + union { + __u64 limit; /* limit number of processed chunks */ + struct { + __u32 limit_min; + __u32 limit_max; + }; + }; __u64 unused[7]; } __attribute__ ((__packed__)); -- cgit v1.2.3-59-g8ed1b