Btrfs: add skip_balance mount option
Since restriper kthread starts involuntarily on mount and can suck cpu
and memory bandwidth add a mount option to forcefully skip it. The
restriper in that case hangs around in paused state and can be resumed
from userspace when it's convenient.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 17e5653..e016060 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2707,15 +2707,19 @@
struct btrfs_balance_control *bctl =
(struct btrfs_balance_control *)data;
struct btrfs_fs_info *fs_info = bctl->fs_info;
- int ret;
+ int ret = 0;
mutex_lock(&fs_info->volume_mutex);
mutex_lock(&fs_info->balance_mutex);
set_balance_control(bctl);
- printk(KERN_INFO "btrfs: continuing balance\n");
- ret = btrfs_balance(bctl, NULL);
+ if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
+ printk(KERN_INFO "btrfs: force skipping balance\n");
+ } else {
+ printk(KERN_INFO "btrfs: continuing balance\n");
+ ret = btrfs_balance(bctl, NULL);
+ }
mutex_unlock(&fs_info->balance_mutex);
mutex_unlock(&fs_info->volume_mutex);