On Jan 28, 2008 2:17 AM, Andi Kleen <ak@xxxxxxx> wrote: > > I completely agree. If one thread writes A and another writes B then the > > kernel should record either A or B, not ((A & 0xffffffff00000000) | (B & > > 0xffffffff)) > > The problem is pretty nasty unfortunately. To solve it properly I think > the file_operations->read/write prototypes would need to be changed > because otherwise it is not possible to do atomic relative updates > of f_pos. Right now the actual update is burrowed deeply in the low level > read/write implementation. But that would be a huge impact all over > the tree :/ If there were a wrapper around reads and writes of f_pos as there is for i_size e.g. it would hit a lot of code, but not as many as I had originally thought. the most important ones are in the vfs itself, where there are only 59 uses of the field (not all need to be changed). ext3 has fewer (25), and cifs only 12 uses. -- Thanks, Steve - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
