[PATCH] fallocate returned values on failure

[Jeremy Allison]

On Thu, Dec 04, 2014 at 02:02:38PM +0800, Jones wrote:
> Hello list,
> 
> There is samba-4.0.5 in the linux box,
> and set strict allocate = yes to go through fallocate api.
> 
> Found if fallocate() returns -1 with errno = ENOSPC,
> cannot catch by error handling as followings:
>     ret = SMB_VFS_FALLOCATE(fsp, VFS_FALLOCATE_EXTEND_SIZE,
>              offset, num_to_write);
>   if (ret == ENOSPC) {
>   errno = ENOSPC;
> ret = -1;
>         goto out;
>   }
> 
> Per man pages said,
> posix_fallocate() returns an error number on failure,
> fallocate() returns -1 on failure.
> 
> Patch as attached could handle -1 returned from fallocate() on failure,
> please help review and any suggestions are appreciated,
> thanks.

Very good catch ! Thanks.

I think the best way to fix this is to
standardize the return from SMB_VFS_FALLOCATE()
to be -1,set errno on error, and then convert
the lower level to do this if it uses posix_fallocate().

We should also fix vfs_slow_fallocate() to
do the same - and then fix all the callers
to expect -1,errno returns instead of errno.

Can you log a bug so we can track this and
get it fixed in 4.0.x and above ?

I'll code a fix up for master, I'd appreciate
it if you could test it !

Thanks,

	Jeremy.