Btrfs: allow for canceling restriper

[deliverable/linux.git] / fs / btrfs / volumes.c

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d32660ce753da9074ceaddef7d8f197cd3613ef2..c32667318ae4b82b34ebecfdd31f48982a52df88 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2492,7 +2492,8 @@ static int __btrfs_balance(struct btrfs_fs_info *fs_info)
        key.type = BTRFS_CHUNK_ITEM_KEY;
 
        while (1) {
-               if (atomic_read(&fs_info->balance_pause_req)) {
+               if (atomic_read(&fs_info->balance_pause_req) ||
+                   atomic_read(&fs_info->balance_cancel_req)) {
                        ret = -ECANCELED;
                        goto error;
                }
@@ -2560,7 +2561,10 @@ error:
 
 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
 {
-       return atomic_read(&fs_info->balance_pause_req) == 0;
+       /* cancel requested || normal exit path */
+       return atomic_read(&fs_info->balance_cancel_req) ||
+               (atomic_read(&fs_info->balance_pause_req) == 0 &&
+                atomic_read(&fs_info->balance_cancel_req) == 0);
 }
 
 static void __cancel_balance(struct btrfs_fs_info *fs_info)
@@ -2586,7 +2590,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
        int ret;
 
        if (btrfs_fs_closing(fs_info) ||
-           atomic_read(&fs_info->balance_pause_req)) {
+           atomic_read(&fs_info->balance_pause_req) ||
+           atomic_read(&fs_info->balance_cancel_req)) {
                ret = -EINVAL;
                goto out;
        }
@@ -2832,6 +2837,42 @@ int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
        return ret;
 }
 
+int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
+{
+       mutex_lock(&fs_info->balance_mutex);
+       if (!fs_info->balance_ctl) {
+               mutex_unlock(&fs_info->balance_mutex);
+               return -ENOTCONN;
+       }
+
+       atomic_inc(&fs_info->balance_cancel_req);
+       /*
+        * if we are running just wait and return, balance item is
+        * deleted in btrfs_balance in this case
+        */
+       if (atomic_read(&fs_info->balance_running)) {
+               mutex_unlock(&fs_info->balance_mutex);
+               wait_event(fs_info->balance_wait_q,
+                          atomic_read(&fs_info->balance_running) == 0);
+               mutex_lock(&fs_info->balance_mutex);
+       } else {
+               /* __cancel_balance needs volume_mutex */
+               mutex_unlock(&fs_info->balance_mutex);
+               mutex_lock(&fs_info->volume_mutex);
+               mutex_lock(&fs_info->balance_mutex);
+
+               if (fs_info->balance_ctl)
+                       __cancel_balance(fs_info);
+
+               mutex_unlock(&fs_info->volume_mutex);
+       }
+
+       BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
+       atomic_dec(&fs_info->balance_cancel_req);
+       mutex_unlock(&fs_info->balance_mutex);
+       return 0;
+}
+
 /*
  * shrinking a device means finding all of the device extents past
  * the new size, and then following the back refs to the chunks.