fs: Remove bogus wait in write_inode_now()

inode_sync_wait() in write_inode_now() is just bogus. That function waits for
I_SYNC bit to be cleared but writeback_single_inode() clears the bit on return
so the wait is effectivelly a nop unless someone else submits the inode for
writeback again. All the waiting write_inode_now() needs is achieved by using
WB_SYNC_ALL writeback mode.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>

fs/fs-writeback.c

@@ -1364,8 +1364,6 @@ int write_inode_now(struct inode *inode, int sync)
 	ret = writeback_single_inode(inode, wb, &wbc);
 	spin_unlock(&inode->i_lock);
 	spin_unlock(&wb->list_lock);
-	if (sync)
-		inode_sync_wait(inode);
 	return ret;
 }
 EXPORT_SYMBOL(write_inode_now);