btrfs-progs: extend balance args to take min/max limit filter

Add the overlapping limit and [limit_min, limit_max] members to the
balance args. The min/max values are interpreted iff the corresponding
flag BTRFS_BALANCE_ARGS_LIMIT_RANGE is set.

The minimum and maximum are inclusive.

Note that the values are only 32bit, but this should be enough for the
foreseeable future.

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 12 insertions, 1 deletions

diff --git a/ioctl.h b/ioctl.h
index dff015a5..e5cf3230 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -227,7 +227,18 @@ 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__));