Btrfs: allow for canceling restriper
Implement an ioctl for canceling restriper. Currently we wait until
relocation of the current block group is finished, in future this can be
done by triggering a commit. Balance item is deleted and no memory
about the interrupted balance is kept.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d32660c..c326673 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2492,7 +2492,8 @@
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 @@
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 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 @@
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.