The disclosed embodiments relate to a mechanism for allowing concurrent access, e.g. write operations, to a data structure, e.g. a file, which may have limited capacity, by multiple processes or threads and, in particular, for allowing concurrent, or otherwise substantially simultaneously, appending of data to the file thereby. Each process/thread requests the amount of space it needs to append its data. Upon request, the disclosed mechanism allocates and reserves the requested amount of space and allows the requesting process/thread to commence its append operation. Subsequent to the commencement of the append operation, another thread is then free to request space for its needs and commence its append operation concurrently, or otherwise substantially simultaneously, with the previous append operation, i.e. before the prior append operation is completed.
