Btrfs: implement online profile changing

Profile changing is done by launching a balance with
BTRFS_BALANCE_CONVERT bits set and target fields of respective
btrfs_balance_args structs initialized.  Profile reducing code in this
case will pick restriper's target profile if it's available instead of
doing a blind reduce.  If target profile is not yet available it goes
back to a plain reduce.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index eac26c359312..79ee9c324562 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -196,6 +196,9 @@ struct map_lookup {
 #define BTRFS_BALANCE_TYPE_MASK         (BTRFS_BALANCE_DATA |       \
                                          BTRFS_BALANCE_SYSTEM |     \
                                          BTRFS_BALANCE_METADATA)
+
+#define BTRFS_BALANCE_FORCE             (1ULL << 3)
+
 /*
  * Balance filters
  */
@@ -205,6 +208,8 @@ struct map_lookup {
 #define BTRFS_BALANCE_ARGS_DRANGE       (1ULL << 3)
 #define BTRFS_BALANCE_ARGS_VRANGE       (1ULL << 4)
 
+#define BTRFS_BALANCE_ARGS_CONVERT      (1ULL << 8)
+
 struct btrfs_balance_args;
 struct btrfs_balance_control {
         struct btrfs_fs_info *fs_info;