Badari Pulavarty wrote:

Amit K. Arora wrote:

quoted

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.

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.

-Eric