On Fri, 2007-03-02 at 09:16 -0600, Eric Sandeen wrote: > Badari Pulavarty wrote: > > > > Amit K. Arora wrote: > > > >> This is to give a heads up on few patches that we will be soon coming up > >> with. These patches implement a new system call sys_fallocate() and a > >> new inode operation "fallocate", for persistent preallocation. The new > >> system call, as Andrew suggested, will look like: > >> > >> asmlinkage long sys_fallocate(int fd, loff_t offset, loff_t len); > >> > > I am wondering about return values from this syscall ? Is it supposed to > > return the > > number of bytes allocated ? What about partial allocations ? > > If you don't have enough blocks to cover the request, you should > probably just return -ENOSPC, not a partial allocation. That could be challenging, when multiple writers are working in parallel. You may not be able to return -ENOSPC, till you fail the allocation (for filesystems which alllocates a block at a time). > > > What about > > if the > > blocks already exists ? What would be return values in those cases ? > > 0 on success, other normal errors oetherwise.. > > If asked for a range that includes already-allocated blocks, you just > allocate any non-allocated blocks in the range, I think. Yes. What I was trying to figure out is, if there is a requirement that interface need to return exact number of bytes it *really* allocated (like write() or read()). I can't think of any, but just wanted to through it out.. BTW, what is the interface for finding out what is the size of the pre-allocated file ? Thanks, Badari - 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
